On Baptism, Against the Donatists

¹⁶ Jader of Midila said: "We know that there is but one baptism in the Catholic Church, and therefore we ought not to admit a heretic unless he has been baptized in our body, lest he should think that he has been baptized outside the Catholic Church."

17. To him our answer is, that if this were said of those unrighteous men who are outside the rock, it certainly would be falsely said. And so it is therefore also in the case of heretics.