16 For this reason, then, we hold them to be enemies, because we speak the truth, because we are afraid to be silent, because we fear to shrink from pressing our point with all the force that lies within our power, because we obey the apostle when he says, "Preach the word; be instant in season out of season; reprove, rebuke, exhort." But, as the gospel says, "They love the praise of men more than the praise of God;" and while they fear to incur blame for a time, they do not fear to incur damnation for ever.
They see, too, themselves what wrong they are doing; they see that they have no answer which they can make, but they overspread the inexperienced with mists, while they themselves are being swallowed up alive—that is, are perishing knowingly and willfully. They see that men are amazed, and look with abhorrence on the fact that they have divided themselves into many schisms, especially in Carthage, the capital and most noted city of all Africa; they have endeavored to patch up the disgrace of their rags.
Thinking that they could annihilate the followers of Maximianus, they pressed heavily on them through the agency of Optatus the Gildonian; they inflicted on them many wrongs amid the cruellest of persecutions. Then they received back some, thinking that all could be converted under the influence of the same terror; but they were unwilling to do those whom they received the wrong of baptizing afresh those who had been baptized by them in their schism, or rather of causing them to be baptized again within their communion by the very same men by whom they had been baptized outside, and thus they at once made an exception to their own impious custom.
They feel how wickedly they are acting in assailing the baptism of the whole world, when they have received the baptism of the followers of Maximianus. But they fear those whom they have themselves rebaptized, lest they should receive no mercy from them, when they have shown it to others; lest these should call them to account for their souls when they have ceased to destroy those of other men.
Source: On Baptism, Against the Donatists (New Advent)