62 Petilianus said: "It will be urged against us, that the Apostle Paul said, ‘One Lord, one faith, one baptism.' We profess that there is only one; for it is certain that those who declare that there are two are mad."
63. Augustine replied: These words of yours are arguments against yourselves; but in your madness you are not aware of it. For the men who say there are two baptisms are those who declare their opinion that the just and the unjust have different baptisms; whereas it belongs neither to one party nor the other, but in both of them is one, being Christ's, although they themselves are not one: and yet the baptism, which is one, the just have to salvation, the unjust to their destruction.
Source: Answer to Letters of Petilian, Bishop of Cirta (New Advent)