What Did the Early Christians Believe About Muhammad?

Christians were among the first people outside Arabia to hear of Muhammad. Within a few years of his death in 632, Arab armies had defeated the Roman and Persian empires, and the Christian communities of Syria, Palestine, Egypt, Armenia and Iraq found themselves living under a new rule. Their notes, chronicles, dialogues and polemics are among the oldest surviving documents that mention him at all.

What did they believe about him? Some Christians assume the early Church saw at once that he was a false prophet; some skeptics argue that the outside sources describe someone so different from the Muslim tradition that the traditional story collapses. Both simplify the evidence. This article reads the earliest Christian writers in date order and asks what they said, what they could have known, and how the Orthodox Church should weigh them.

In brief

The earliest Christian references to Muhammad are brief and mostly practical. A Greek dialogue set in 634, the Teaching of Jacob, reports second-hand rumors of "a prophet" who had appeared "with the Saracens" and dismisses him because prophets do not come with swords. A Syriac chronicle of about 640 simply records a battle in 634 against "the Arabs of Muhammad." An Armenian history written soon after 661 describes him, surprisingly neutrally, as a merchant who preached the God of Abraham. Late seventh-century Syriac writers call him the Arabs' "guide" or "leader." Only in the eighth century do we find a sustained theological verdict, in the chapter on the "Ishmaelites" attributed to St John of Damascus, which calls him a false prophet. By contrast, the Patriarch Timothy I, in his famous debate before the caliph al-Mahdi (781 or 782), praised Muhammad for walking "in the path of the prophets" while declining to accept him as a prophet. These sources confirm that Muhammad was a real seventh-century leader, and show that Christian opinion about him formed gradually.

Thesis: The earliest Christians did not share one fixed view of Muhammad; they moved from rumor and chronicle to considered theological judgment over about a century, and an honest Orthodox reading should let both their agreement (Christ is the final revelation) and their diversity of tone stand.

Why outside sources matter, and their limits

The fullest Muslim biography of Muhammad goes back to Ibn Ishaq, who died around 767, so historians value seventh-century outsiders as earlier and independent witnesses. (The site's articles on what the earliest sources tell us about Muhammad and on the Qur’an, sīra, hadith and inscriptions cover the Islamic side.) But early is not the same as well informed. These writers were often far from Arabia, heard reports secondhand, and had their own concerns. Some were Chalcedonian (in communion with Constantinople), some Syriac Orthodox, some of the Church of the East, one Armenian.

The primary historical evidence

634: "a prophet ... coming with the Saracens"

The Teaching of Jacob Newly Baptized (Doctrina Jacobi) is a Greek dialogue set among Jews forcibly baptized at Carthage under the Emperor Heraclius. Its translator, Andrew Jacobs, notes that the action takes place in the spring and summer of 634.¹ Near the end, a Jew named Justus reads out a letter from his brother Abraham in Palestine. When the Roman candidatus (a military officer) "was slaughtered by the Saracens," Abraham writes, "they said that a prophet appeared, coming with the Saracens and he is proclaiming the arrival of the coming Anointed One and Christ." Abraham asked "a certain very scriptural old man" what he thought. The old man groaned: "He is a deceiver. Do prophets come with swords and chariots?" Abraham then made inquiries and heard "that you find nothing true in this so-called prophet, except shedding human blood. For he says that he has keys of Paradise which is unbelievable."²

This is probably the earliest surviving reference to Muhammad, but Muhammad is not named, and the report is a rumor inside a letter inside a dialogue written to persuade Jews that Christ has already come. The "prophet" proclaims a coming Messiah, which fits no later Muslim account. The judgment is moral rather than doctrinal: a man who comes with the sword is not a prophet. The historian Patricia Crone, known for her skepticism toward the traditional narrative, described what is evidently this passage as coming from a Greek text "written during the Arab invasion of Syria between 632 and 634" and concluded: "There is no doubt that Mohammed existed, occasional attempts to deny it notwithstanding."³ The work is usually dated to 634 or soon after, though Peter von Sivers has argued for the end of the seventh century in a 2022 conference paper.⁴ {{strong: The Teaching of Jacob, set in 634, reports rumors of a prophet who had appeared with the Arab armies.}}

About 640: "the Arabs of Muhammad"

The first Christian text to name Muhammad is a dry chronicle entry. A Syriac chronicle attributed to Thomas the Presbyter, composed around 640 and preserved in an eighth-century manuscript (the so-called Chronicle of 724), records that in February of the Seleucid year 945 (634) there was, in the English rendering quoted by Sidney Griffith from Robert Hoyland, "a battle between the Romans and the Arabs of Muḥammad in Palestine twelve miles east of Gaza." The older Latin version of the same entry by Jean-Baptiste Chabot gives the day as Friday, 4 February, and adds that the Romans fled and that many poor villagers of Palestine, "christiani, iudaei et samaritani," were killed.⁵ Griffith calls it "the so-far earliest known Christian reference to Muḥammad by name."⁶ {{very-strong: A Syriac chronicle of about 640 names Muhammad as the leader of the Arabs who fought the Romans near Gaza in 634.}}

The chronicler passes no religious judgment at all. A damaged note on the first leaf of a Syriac Gospel manuscript in the British Library (Add. 14,461) may be even closer to events. William Wright, who catalogued it in 1870, wrote that it "seems to be a nearly contemporary notice of the taking of Damascus by the Arabs."⁷ Much of it is illegible, and what it says about Muhammad, if anything, cannot be settled from the catalogue.

"644": a debate that may be later

A Syriac letter describes the Syriac Orthodox Patriarch John (d. 648) being questioned by a Muslim emir on Sunday, 9 May; scholars following François Nau have usually placed this in 644. Barbara Roggema has argued that the dating is fragile. The emir's last question, about inheritance law, presupposes Qur’anic rules and Christian anxieties that belong to a much later period, and she concludes that at least that part of the text "is closer in time to the production of the manuscript, the year 874, than to the lifetime of Patriarch John Sedra." She also notes that the debate does not touch "Muhammad's prophethood" at all.⁸ It should not be cited as a record of what Christians said about Muhammad in 644.

After 661: Sebeos's "preacher" of the God of Abraham

The Armenian history attributed to Bishop Sebeos ends with Mu‘awiya's rise to the caliphate in 661, and its author seems to have written close to those events. In Robert Thomson's translation:

At that time a certain man from among those same sons of Ismael whose name was Mahmet, a merchant, as if by God’s command appeared to them as a preacher and the path of truth. He taught them to recognize the God of Abraham, especially because he was learned and informed in the history of Moses.⁹

Sebeos adds that Muhammad "legislated for them: not to eat carrion, not to drink wine, not to speak falsely, and not to engage in fornication," and that he urged them, as sons of Abraham, to claim the land God had promised Abraham.¹⁰ Sebeos's framework is biblical (the Arabs are Hagar's descendants), but his Muhammad is a monotheist preacher with a moral law. Some details, such as the role he gives to Jewish refugees from Edessa, appear in no Muslim source and have fed modern revisionist theories.

An East Syrian chronicle from Khuzistan in Persia, usually dated to the 660s or a little later, likewise describes the Arab invaders as sent by God and gives their leader's name in passing; in Ignazio Guidi's Latin version, "quorum rector fuit Muhammad," "whose leader was Muhammad."¹¹

The 680s and 690s: the "guide" and the merchant

John bar Penkaye, a monk of the Church of the East in northern Mesopotamia, wrote his summary of world history around 687, soon after a plague that he says began in "the sixty-seventh year of the empire of the Arabs" (686). The Arabs, he says, had received "from the man who was their guide, an order in favour of the Christians and the monks," and through his guidance "they held to the worship of one God, according to the customs of the old law." They were "so attached to the tradition of Muhammad who was their leader, that they inflicted the death penalty on anyone who seemed not to obey his commands." Of the caliph Mu‘awiya he writes, "Justice flourished under his reign," and the Arabs "required only the tribute, and left him free to hold any belief."¹² John was not praising Islam as true. He calls the conquerors a "barbarian kingdom" that God raised up against Christians because of their divisions and sins, and he treats the disasters of his own day as further punishment.

The Syriac Orthodox scholar Jacob of Edessa (about 630 to 708) noted in his chronicle that "descendit Muhammat ob mercaturam," Muhammad went down for trade into Palestine and neighboring regions (translated here from Brooks's Latin).¹³

The eighth century: John of Damascus and the "heresy of the Ishmaelites"

St John of Damascus, a Chalcedonian monk from a family that had served the Umayyad caliphs, compiled his Fount of Knowledge late in life; Frederic Chase notes that it is dedicated to Cosmas as bishop of Maiuma and so "could not have been composed before 743." The treatise on heresies inside it may be older: Schadler reports a suggestion that it predates 726.¹⁴ The middle part, On Heresies, ends with a chapter that begins:

There is also the superstition of the Ishmaelites which to this day prevails and keeps people in error, being a forerunner of the Antichrist.¹⁵

The chapter continues that "a false prophet named Mohammed has appeared in their midst. This man, after having chanced upon the Old and New Testaments and likewise, it seems, having conversed with an Arian monk, devised his own heresy." It summarizes Qur’anic teaching about Christ with some accuracy (born of Mary without seed, the Word and Spirit of God but a creature, not crucified), then presses the question of witnesses: "which of the prophets foretold that such a prophet would rise up?"¹⁶ The later sections are sharp and sometimes mocking.

Two cautions apply. First, authorship: the chapter has been doubted, though its modern editors attribute it to John wholly or in part. Peter Schadler concludes that "at the minimum he took the text and supplemented it, and at most wrote the full text himself."¹⁷ The site's life of St John of Damascus sets out that debate. Second, the common claim that John called Islam a "Christian heresy" goes beyond the text. John defines heresy broadly, and his catalogue names Hellenism and Judaism among the four "parents and archetypes of all heresies." Schadler finds that while John may have counted Islam a heresy in that wide sense, "there is no evidence he saw Islam as a specifically ‘Christian heresy’."¹⁸ {{moderate: John of Damascus wrote, or substantially shaped, the earliest systematic Christian refutation of Muhammad's prophethood.}}

781 or 782: Timothy I before the caliph

The most quoted early Christian statement about Muhammad is by Timothy I, Catholicos of the Church of the East (727/8 to 823). Over two days he answered the questions of the Abbasid caliph al-Mahdi and then wrote up the conversation in Syriac. Alphonse Mingana, who translated it in 1928, dates the debate "towards the end of A.D. 781 or at the latest 782" and cautions that "It is not necessary to suppose that every word in it was uttered verbatim."¹⁹

Asked whether Christ or the Gospel foretold Muhammad, Timothy answers plainly: "So far as Muhammad is concerned I have not received a single testimony either from Jesus Christ or from the Gospel which would refer to his name or to his works." He then explains that the Paraclete promised by Jesus is the Spirit of God, not a later man.²⁰ But when the caliph asks, "What do you say about Muhammad?", Timothy replies:

Muhammad is worthy of all praise, by all reasonable people, O my Sovereign. He walked in the path of the prophets, and trod in the track of the lovers of God.²¹

He explains that Muhammad taught one God, drew people from idolatry and from bad works, and showed zeal for God. When al-Mahdi concludes, "You should, therefore, accept the words of the Prophet," Timothy accepts only the belief in one God, which he says "I have learned from the Torah, from the Prophets and from the Gospel," and goes on to defend the Trinity.²² This is court diplomacy, but also Timothy's considered position: in his view, Muhammad deserves honor for opposing idolatry, yet Christians receive no new revelation from him. That assessment is Timothy's own, not an Orthodox recognition of Muhammad as a prophet; the Orthodox position is set out below.

Patterns in the evidence

The earliest writers saw Muhammad mainly as the leader of the Arabs and rarely engaged his teaching; they were trying to explain conquest. Detailed theological engagement arrives only once Christians had lived under Muslim rule for several generations and could read or hear the Qur’an's claims about Christ. And the later and more polemical stories, such as the monk who supposedly taught Muhammad, grew in the eighth and ninth centuries; the Syriac legend of the monk Sergius Bahira, as Griffith notes, is a ninth-century composition.²³

The Orthodox position

Dogma. The Orthodox Church has never issued a conciliar definition about Muhammad. Its dogma is the faith of the Creed and the councils: Jesus Christ is the eternal Son of God, true God and true man, crucified and risen, and in Him God's revelation is complete. St Paul's warning applies to any later claim to correct it: "even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed" (Galatians 1:8, NKJV). Muslims believe Muhammad is "seal [i.e., last] of the prophets" (Qur’an 33:40, Saheeh International).²⁴ The two claims cannot both be true, and Orthodox Christians cannot accept Muhammad as a prophet. The Qur’an's denial of the Crucifixion and of the Son's divinity, which John of Damascus already noted, is where the disagreement lies (see the site's discussion of whether the Qur’an misunderstands the Trinity).

Common tradition. St John of Damascus is a saint and Father of the Church, and his chapter shaped Byzantine writing on Islam for centuries. His core arguments (the lack of prophetic witnesses, the denial of the Cross) remain standard, but a Father's polemical tone, or the details of his information, are not dogma.

Theological opinion. How to speak of Muhammad as a person, and of his turning Arabia from idols to one God, is a matter where Christians have differed from the beginning. Timothy I belonged to the Church of the East, not the Orthodox communion, yet an Orthodox Christian can respect his mix of firmness and courtesy. Jesus's test, "You will know them by their fruits" (Matthew 7:16, NKJV), is a reason to judge teaching firmly and to describe a neighbor's faith fairly.

The scholarly debates

In Hagarism: The Making of the Islamic World (1977), Patricia Crone and Michael Cook tried to reconstruct early Islam largely from these outside sources rather than from later Muslim tradition. As Fred Donner summarizes their argument, they proposed that Muhammad and the first believers preached the imminent coming of a Messiah, whom they identified with the second caliph, ‘Umar, and they drew on Jewish and Christian sources of the period. Such texts attracted them: the Doctrina's prophet proclaims "the coming Anointed One," and Sebeos stresses Abraham, the Jews and the Promised Land. At its strongest, the argument is that the earliest witnesses describe a movement focused on Jerusalem and the end of the age, which later tradition smoothed over.²⁵

The specific reconstruction has been heavily criticized. Donner concluded that there is no reason to believe the messianic idea was present among the believers of Muhammad's time.²⁶ The authors themselves later stepped back. In 2006 the legal scholar Liaquat Ali Khan, a sharp Muslim critic of the book, reported that Cook told him, and then confirmed by email: "The central thesis of that book was, I now think, mistaken."²⁷ Crone, as quoted above, affirmed in 2008 that Muhammad's existence is beyond doubt. Yet the book's method, taking non-Muslim sources seriously, has lasted, and Christians should not use the authors' retreat to dismiss the real differences between the earliest outside reports and the later sīra.

The strongest objections

"These are hostile outsiders who did not understand Islam"

A Muslim reader may say that these writers were defeated enemies who relied on rumor, and that John of Damascus wrote with contempt. This is partly fair. But the sources are not uniformly hostile. Thomas the Presbyter is neutral in tone, Sebeos fairly respectful, John bar Penkaye full of praise for the peace of Mu‘awiya's reign, and Timothy admiring of Muhammad's monotheism. On the bare facts (Muhammad's existence, leadership, monotheism and moral law) the evidence agrees with Muslim tradition.

"The Torah and Gospel foretold Muhammad"

The Qur’an says that believers follow "the unlettered prophet, whom they find written [i.e., described] in what they have of the Torah and the Gospel" (7:157), and that Jesus brought "good tidings of a messenger to come after me, whose name is Aḥmad" (61:6, Saheeh International).²⁸ The caliph pressed Timothy with the Paraclete of John's Gospel, and Timothy answered from the text: Jesus promised that the Father "will give you another Helper, that He may abide with you forever" (John 14:16, NKJV), and Timothy identifies that Helper as the Spirit of God. The fuller case is set out in the site's article on whether Muhammad is predicted in the Bible.

"The early Christians all knew he was a false prophet"

Some Christian apologists present the earliest sources as a united verdict. The evidence does not allow that. The earliest surviving sustained refutation is the Damascene chapter of the first half of the eighth century; the Doctrina's "deceiver" is an unnamed rumor in a Jewish character's mouth; the seventh-century chroniclers mostly record rather than judge; and an eighth-century catholicos praised Muhammad in front of the caliph. The Christian conclusion that Muhammad was not a prophet rests on the Gospel, not on a uniform early consensus that did not exist.

What we can say confidently

• Christian sources from the 630s and 640s refer to a leader of the Arab conquerors; a Syriac chronicle of about 640 names him as Muhammad.
• These sources, independent of later Muslim tradition, establish that Muhammad was a real seventh-century figure who led the Arabs and preached one God.
• Seventh-century Christian writers mostly treated him as a political and military leader.
• Sustained theological refutation appears in the eighth century, above all in the chapter on the Ishmaelites associated with St John of Damascus.
• Christian writers differed in tone, from the Damascene's polemic to Timothy I's courteous praise, while agreeing that Muhammad was not a prophet to be followed.

What remains disputed

• {{debated: The exact date of the Teaching of Jacob, and whether its rumor reflects Muhammad's own preaching.}}
• How much reliable information about Muhammad's teaching Sebeos and other distant writers possessed.
• Whether John of Damascus wrote the whole chapter on the Ishmaelites or adapted an existing text.
• Whether the debate between Patriarch John and the emir reflects a real meeting in 644 or a later composition.
• How far the differences between the earliest outside reports and the later Muslim biography point to real changes in early Islam, rather than ignorance or polemic.

Conclusion

The first Christians to hear of Muhammad were watching empires fall, and their earliest words about him are a rumor, a battle notice and a name. As Muslims pressed the claim that Muhammad completed the revelation given to Moses and Jesus, Christian thinkers answered: firmly in St John of Damascus, courteously in Timothy I. Their common conviction is the faith of the Church, that God has spoken His final Word in His Son, crucified and risen, who tramples down death by death. Christians who believe they have the truth have no need to overstate the evidence, and the best early witnesses show that one can refuse a prophetic claim while speaking honestly and charitably about the one who made it. The Church Fathers are worth reading in full for exactly that reason.

Notes

1. Andrew S. Jacobs, introduction to Teaching of Jacob Newly Baptized: English Translation, andrewjacobs.org, translated from the Greek text edited by Vincent Déroche, "Doctrina Jacobi," Travaux et Mémoires 11 (1991): 71-219. ↩
2. Doctrina Jacobi V.16, Jacobs trans., Déroche pp. 209-211. ↩
3. Patricia Crone, "What do we actually know about Mohammed?", openDemocracy, 10 June 2008. ↩
4. Peter von Sivers, conference draft presented at the Seventh Inarah Symposium, Trier, 2022, as listed on his Academia.edu page. ↩
5. English: Sidney H. Griffith, "Islam, Syriac interactions with," in Gorgias Encyclopedic Dictionary of the Syriac Heritage, electronic edition (Beth Mardutho), citing R. G. Hoyland, Seeing Islam as Others Saw It (Princeton: Darwin Press, 1997), 120. Latin: Chronicon miscellaneum ad annum Domini 724 pertinens, ed. E. W. Brooks, Latin trans. J.-B. Chabot, in Chronica Minora, pars secunda, CSCO Scriptores Syri, series 3, vol. 4 (Paris). ↩
6. Griffith, "Islam, Syriac interactions with," GEDSH. ↩
7. William Wright, Catalogue of Syriac Manuscripts in the British Museum Acquired since the Year 1838, part 1 (London, 1870), 65-66, on Add. 14,461, fol. 1. ↩
8. Barbara Roggema, "The Debate between Patriarch John and an Emir of the Mhaggrāyē: A Reconsideration of the Earliest Christian-Muslim Debate," in Martin Tamcke, ed., Christians and Muslims in Dialogue in the Islamic Orient of the Middle Ages (Beirut: Orient-Institut; Würzburg: Ergon, 2007), 21-39, at 26 (date) and 39 (quotations). ↩
9. The Armenian History Attributed to Sebeos, trans. R. W. Thomson, with historical commentary by James Howard-Johnston, Translated Texts for Historians 31 (Liverpool: Liverpool University Press, 1999), ch. 42 in this numbering (ch. 30 in older editions); text consulted at historians.armeniancathedral.org (Sebeos 42:5). On the date, Crone, "What do we actually know," and the work's closing events. ↩
10. Sebeos, ch. 42 (42:6-7), Thomson trans. ↩
11. Chronicon anonymum (the Khuzistan Chronicle), ed. and Latin trans. Ignazio Guidi, Chronica Minora, pars prior, CSCO Scriptores Syri, series 3, vol. 4 (Paris, 1903). The English is translated here from Guidi's Latin. ↩
12. John bar Penkaye, Rish Melle 15, English online edition by Roger Pearse (tertullian.org, 2010), drawing on Alphonse Mingana's French (Sources syriaques, vol. 1, Mosul, 1908) and Sebastian Brock, "North Mesopotamia in the Late Seventh Century: Book XV of John Bar Penkāyē's Rīš Mellē," Jerusalem Studies in Arabic and Islam 9 (1987): 51-75. The "sixty-seventh year" is dated to 686 in Brock's note. ↩
13. Chronicon Iacobi Edesseni, Latin trans. E. W. Brooks, Chronica Minora, pars tertia, CSCO Scriptores Syri, series 3, vol. 4 (Paris). Jacob's dates from Griffith et al., GEDSH, "Yaʿqub of Edessa." ↩
14. Frederic H. Chase Jr., introduction to Saint John of Damascus: Writings, Fathers of the Church 37 (Washington, DC: Catholic University of America Press, 1958), xxv. ↩
15. John of Damascus, On Heresies 101 (100 in Kotter's edition), Chase trans., 153. ↩
16. On Heresies 101, Chase trans., 153-154. ↩
17. Peter Schadler, John of Damascus and Islam: Christian Heresiology and the Intellectual Background to Earliest Christian-Muslim Relations, History of Christian-Muslim Relations 34 (Leiden: Brill, 2018), introduction. ↩
18. Schadler, John of Damascus and Islam, ch. 1 (the introduction reports the suggested pre-726 date of On Heresies); for the four "parents and archetypes," On Heresies, opening, Chase trans., 111. ↩
19. A. Mingana, "The Apology of Timothy the Patriarch before the Caliph Mahdi," Woodbrooke Studies 3, Bulletin of the John Rylands Library 12, no. 1 (1928): 137-298, at 147. Timothy's dates from GEDSH, "Timotheos I." ↩
20. Mingana, "Apology," 169-170. ↩
21. Mingana, "Apology," 197. ↩
22. Mingana, "Apology," 197-198. ↩
23. Griffith, "Islam, Syriac interactions with," GEDSH. ↩
24. The Holy Bible, New King James Version; Qur’an 33:40, Saheeh International translation, quran.com. ↩
25. Patricia Crone and Michael Cook, Hagarism: The Making of the Islamic World (Cambridge: Cambridge University Press, 1977), as summarized in Fred M. Donner, "La question du messianisme dans l'islam primitif," Revue des mondes musulmans et de la Méditerranée 91-94 (2000): 17-28, abstract. ↩
26. Donner, "La question du messianisme," abstract and conclusion. ↩
27. Liaquat Ali Khan, "Hagarism: The Story of a Book Written by Infidels for Infidels," commentary, The Baltimore Chronicle, 26 April 2006, quoting an email from Michael Cook. ↩
28. Qur’an 7:157 and 61:6, Saheeh International translation, quran.com. ↩

Bibliography

Primary sources

• Doctrina Jacobi nuper baptizati. Greek text ed. Vincent Déroche, Travaux et Mémoires 11 (1991): 71-219. English: Andrew S. Jacobs, Teaching of Jacob Newly Baptized: English Translation, andrewjacobs.org.
• Chronica Minora, partes I-III. Ed. I. Guidi, E. W. Brooks and J.-B. Chabot. Corpus Scriptorum Christianorum Orientalium, Scriptores Syri, series 3, vol. 4. Paris, 1903 and following years (includes the chronicle of 724 containing Thomas the Presbyter's entries, the Khuzistan Chronicle and the Chronicle of Jacob of Edessa).
• The Armenian History Attributed to Sebeos. Translated by R. W. Thomson, with historical commentary by James Howard-Johnston and Tim Greenwood. Translated Texts for Historians 31. Liverpool: Liverpool University Press, 1999.
• John bar Penkaye. Summary of World History (Rish Melle), book 15. Online English edition by Roger Pearse, tertullian.org, 2010, from A. Mingana, Sources syriaques (Mosul, 1908), and S. P. Brock (1987).
• John of Damascus. Saint John of Damascus: Writings. Translated by Frederic H. Chase Jr. The Fathers of the Church 37. Washington, DC: Catholic University of America Press, 1958.
• Timothy I. "The Apology of Timothy the Patriarch before the Caliph Mahdi." Edited and translated by A. Mingana. Woodbrooke Studies 3. Bulletin of the John Rylands Library 12, no. 1 (1928): 137-298.
• Wright, William. Catalogue of Syriac Manuscripts in the British Museum Acquired since the Year 1838. Part 1. London, 1870.
• The Holy Bible, New King James Version. Nashville: Thomas Nelson, 1982.

Orthodox and patristic sources

• Schadler, Peter. John of Damascus and Islam: Christian Heresiology and the Intellectual Background to Earliest Christian-Muslim Relations. History of Christian-Muslim Relations 34. Leiden: Brill, 2018.
• Chase, Frederic H., Jr. Introduction to Saint John of Damascus: Writings (above).

Other scholarship (including scholars who disagree)

• Brock, Sebastian P. "North Mesopotamia in the Late Seventh Century: Book XV of John Bar Penkāyē's Rīš Mellē." Jerusalem Studies in Arabic and Islam 9 (1987): 51-75.
• Crone, Patricia. "What do we actually know about Mohammed?" openDemocracy, 10 June 2008.
• Crone, Patricia, and Michael Cook. Hagarism: The Making of the Islamic World. Cambridge: Cambridge University Press, 1977.
• Donner, Fred M. "La question du messianisme dans l'islam primitif." Revue des mondes musulmans et de la Méditerranée 91-94 (2000): 17-28.
• Griffith, Sidney H. "Islam, Syriac interactions with." In Gorgias Encyclopedic Dictionary of the Syriac Heritage, ed. Sebastian P. Brock, Aaron M. Butts, George A. Kiraz and Lucas Van Rompay. Electronic edition, Beth Mardutho.
• Hoyland, Robert G. Seeing Islam as Others Saw It: A Survey and Evaluation of Christian, Jewish and Zoroastrian Writings on Early Islam. Studies in Late Antiquity and Early Islam 13. Princeton, NJ: Darwin Press, 1997.
• Roggema, Barbara. "The Debate between Patriarch John and an Emir of the Mhaggrāyē: A Reconsideration of the Earliest Christian-Muslim Debate." In Christians and Muslims in Dialogue in the Islamic Orient of the Middle Ages, ed. Martin Tamcke, 21-39. Beirut: Orient-Institut; Würzburg: Ergon, 2007.

Sources from the tradition discussed (Islamic)

• The Qur’an. Saheeh International translation. quran.com.
• Khan, Liaquat Ali. "Hagarism: The Story of a Book Written by Infidels for Infidels." The Baltimore Chronicle, 26 April 2006.