14 Accordingly, I too might use the words of the blessed Cyprian to turn the hearts of those that hear me to the consideration of something truly marvellous, if I were to say "that John, who was accounted greater among the prophets—he who was filled with divine grace while yet in his mother's womb; he who was upheld in the spirit and power of Elias; who was not the adversary, but a forerunner and herald of the Lord: who not only foretold our Lord in words, but also showed Him to the sight; who baptized Christ Himself, through whom all others are baptized," — he was not worthy to baptize in such wise that those who were baptized by him should not be baptized again after him; and shall no one think that a man should be baptized in the Church after he had been baptized by the covetous, by defrauders, by extortioners, by usurers?
Is not the answer ready to this invidious question, Why do you think this unmeet, as though either John were dishonored, or the covetous man honored? But His baptism ought not to be repeated, of whom John says, "The same is He which baptizes with the Holy Ghost." For whoever be the minister by whose hands it is given, it is His baptism of whom it was said, "The same is He which baptizes." But neither was the baptism of John himself repeated, when the Apostle Paul commanded those who had been baptized by him to be baptized in Christ. For what they had not received from the friend of the Bridegroom, this it was right that they should receive from the Bridegroom Himself, of whom that friend had said, "The same is He which baptizes with the Holy Ghost."
Source: On Baptism, Against the Donatists (New Advent)