Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 34

Chapter 34.—79.  Petilianus said:  "For if the apostles were allowed to baptize those whom John had washed with the baptism of repentance, shall it not likewise be allowed to me to baptize men guilty of sacrilege like yourselves?"

80.  Augustin answered:  Where then is what you said above, that there was not one baptism of John and another of Christ, but that there was one baptism, consecrated in three stages, of which three stages John gave the water, Christ the Spirit, and the Comforter the fire?  Why then did the apostles repeat the water in the case of those to whom John had already administered water belonging to the one baptism which is consecrated in three stages?  Surely you must see how necessary it is that every one should understand the meaning of what he is discussing.