Cyril’s Lectures give us a full account of how the Catholic Church had,
by the 4th century, come to understand the meaning of baptism. Cyril called
baptism “the bath of regeneration” and taught his catechumens that it had three
main effects. First, it washed away the guilt of all sins committed prior to
baptism. Second, it sanctified the baptised person, by conferring on him
spiritual union with Christ in His death and resurrection, the gift of the
Spirit, and adoption as God’s child. Third, it impressed a “seal” or permanent
mark on the soul, by virtue of which the baptised person was set apart as the
Holy Spirit’s temple. Cyril’s doctrine of baptism was the view held by all
Christians in the 4th century, and indeed from the 150s onward. (Nick
Needham, 2000 Years of Christ's Power, 4 vols. [revised ed.; Ross-Shire:
Christian Focus, 2016], 1:197-98)
