Justin Martyr describes Christian washing as being ‘for the remission of sins, and unto regeneration’ (First Apology 61, 66). Tertullian calls baptism the seal of faith and speaks of the washing by which sins are remitted (On Baptism). Gregory of Nyssa is equally direct: baptism is purification, remission, renovation, and regeneration (On the Baptism of Christ).
The Fathers can use symbols and types when explaining baptism, but ‘symbol’ does not mean ‘empty.’ For them the visible water belongs to a divine act of incorporation and new birth. That consensus does not erase disagreements over preparation, infant baptism, rebaptism, or how grace operates. It does rule out presenting the historic patristic position as a bare public testimony with no sacramental efficacy.
Primary sources
Justin Martyr, First Apology 61 and 66: https://www.newadvent.org/fathers/0126.htm
Tertullian, On Baptism: https://www.newadvent.org/fathers/0321.htm
Gregory of Nyssa, On the Baptism of Christ: https://www.newadvent.org/fathers/2910.htm