Augustine of Hippo, On the Grace of Christ, and on Original Sin II.5: Cœlestius’ Book Which Was Produced in the Proceedings at Rome

But in the book which he published at Rome, and produced in the proceedings before the church there, he so speaks on this question as to show that he really believes what he had professed to be in doubt about. For these are his words: “That infants, however, ought to be baptized for the remission of sins, according to the rule of the Church universal, and according to the meaning of the Gospel, we confess. For the Lord has determined that the kingdom of heaven should only be conferred on baptized persons; and since the resources of nature do not possess it, it must necessarily be conferred by the gift of grace.” Now if he had not said anything elsewhere on this subject, who would not have supposed that he acknowledged the remission of original sin even in infants at their baptism, by saying that they ought to be baptized for the remission of sins? Hence the point of what you have stated in your letter, that Pelagius’ answer to you was on this wise, “That infants are baptized with the same words of sacramental formula as adults,” and that you were rejoiced to hear the very thing which you were desirous of hearing, and yet that you preferred holding a consultation with us concerning his words.