18 But I say to you yourself, whoever you are, Are you better than John? You will not venture to say: I am better than John. Then let your own baptize after you if they are better. For if baptism was administered after John, blush that baptism is not administered after you. You will say, But I have and teach the baptism of Christ. Acknowledge, then, now the Judge, and do not be a proud herald. You give the baptism of Christ, therefore baptism is not administered after you: after John it was administered, because he gave not the baptism of Christ, but his own; for he had in such manner received it that it was his own.
You are then not better than John: but the baptism given through you is better than that of John; for the one is Christ's, but the other is that of John. And that which was given by Paul, and that which was given by Peter, is Christ's; and if baptism was given by Judas it was Christ's. Judas gave baptism and after Judas baptism was not repeated; John gave baptism, and baptism was repeated after John: because if baptism was given by Judas, it was the baptism of Christ; but that which was given by John, was John's baptism.
We prefer not Judas to John; but the baptism of Christ, even when given by the hand of Judas, we prefer to the baptism of John, rightly given even by the hand of John. For it was said of the Lord before He suffered, that He baptized more than John; then it was added: “Howbeit, Jesus Himself baptized not, but His disciples.” He, and not He: He by power, they by ministry; they performed the service of baptizing, the power of baptizing remained in Christ. His disciples, then, baptized, and Judas was still among his disciples: and were those, then, whom Judas baptized not again baptized; and those whom John baptized were they again baptized?
Plainly there was a repetition, but not a repetition of the same baptism. For those whom John baptized, John baptized; those whom Judas baptized, Christ baptized. In like manner, then, they whom a drunkard baptized, those whom a murderer baptized, those whom an adulterer baptized, if it was the baptism of Christ, were baptized by Christ. I do not fear the adulterer, the drunkard, or the murderer, because I give heed unto the dove, through whom it is said to me, “This is He which baptizes.”
Source: Tractates on the Gospel of John (New Advent)