22 Are we perchance to say, in answer to this, that in the infant the body alone is the cause of sin; but that for each body a new soul is made, and that if this soul live according to the precepts of God, by the help of the grace of Christ, the reward of being made incorruptible may be secured for the body itself, when subdued and kept under the yoke; and that inasmuch as the soul of an infant cannot yet do this, unless it receive the sacrament of Christ, that which could not yet be obtained for the body by the holiness of the soul is obtained for it by the grace of this sacrament; but if the soul of an infant depart without the sacrament, it shall itself dwell in life eternal, from which it could not be separated, as it had no sin, while, however, the body which it occupied shall not rise again in Christ, because the sacrament had not been received before its death?
23. This opinion I have never heard or read anywhere. I have, however, certainly heard and believed the statement which led me to speak thus, namely, “The hour is coming, in the which all that are in the graves shall hear His voice, and shall come forth; they that have done good, unto the resurrection of life,”— the resurrection, namely, of which it is said that “by one man came the resurrection of the dead,” and in which “all shall be made alive in Christ,”— “and they that have done evil, unto the resurrection of damnation.” Now, what is to be understood regarding infants which, before they could do good or evil, have quitted the body without baptism? Nothing is said here concerning them. But if the bodies of these infants shall not rise again, because they have never done either good or evil, the bodies of the infants that have died after receiving the grace of baptism shall also have no resurrection, because they also were not in this life able to do good or evil. If, however, these are to rise among the saints, i.e. among those who have done good, among whom shall the others rise again but among those who have done evil— unless we are to believe that some human souls shall not receive, either in the resurrection of life, or in the resurrection of damnation, the bodies which they lost in death? This opinion, however, is condemned, even before it is formally refuted, by its absolute novelty; and besides this, who could bear to think that those who run with their infant children to have them baptized, are prompted to do so by a regard for their bodies, not for their souls? The blessed Cyprian, indeed, said, in order to correct those who thought that an infant should not be baptized before the eighth day, that it was not the body but the soul which behooved to be saved from perdition— in which statement he was not inventing any new doctrine, but preserving the firmly established faith of the Church; and he, along with some of his colleagues in the episcopal office, held that a child may be properly baptized immediately after its birth.
24. Let every man, however, believe anything which commends itself to his own judgment, even though it run counter to some opinion of Cyprian, who may not have seen in the matter what should have been seen. But let no man believe anything which runs counter to the perfectly unambiguous declaration, that by the offense of one all are brought into condemnation, and that from this condemnation nothing sets men free but the grace of God through our Lord Jesus Christ, in whom alone life is given to all who are made alive. And let no man believe anything which runs counter to the firmly grounded practice of the Church, in which, if the sole reason for hastening the administration of baptism were to save the children, the dead as well as the living would be brought to be baptized.
25. These things being so, it is necessary still to investigate and to make known the reason why, if souls are created new for every individual at his birth, those who die in infancy without the sacrament of Christ are doomed to perdition; for that they are doomed to this if they so depart from the body is testified both by Holy Scripture and by the holy Church. Wherefore, as to that opinion of yours concerning the creation of new souls, if it does not contradict this firmly grounded article of faith, let it be mine also; but if it does, let it be no longer yours.
26. Let it not be said to me that we ought to receive as supporting this opinion the words of Scripture in Zechariah, “He forms the spirit of man within him,” and in the book of Psalms, “He forms their hearts severally.” We must seek for the strongest and most indisputable proof, that we may not be compelled to believe that God is a judge who condemns any soul which has no fault. For to create signifies either as much or, probably, more than to form [fingere]; nevertheless it is written, “Create in me a clean heart, O God,” and yet it cannot be supposed that a soul here expresses a desire to be made before it has begun to exist. Therefore, as it is a soul already existing which is created by being renewed in righteousness, so it is a soul already existing which is formed by the moulding power of doctrine. Nor is your opinion, which I would willingly make my own, supported by that sentence in Ecclesiastes, “Then shall the dust return to the earth as it was: and the spirit shall return to God who gave it.” Nay, it rather favours those who think that all souls are derived from one; for they say that, as the dust returns to the earth as it was, and yet the body of which this is said returns not to the man from whom it was derived, but to the earth from which the first man was made, the spirit in like manner, though derived from the spirit of the first man, does not return to him but to the Lord, by whom it was given to our first parent. Since, however, the testimony of this passage in their favour is not so decisive as to make it appear altogether opposed to the opinion which I shall gladly see vindicated, I thought proper to submit these remarks on it to your judgment, to prevent you from endeavouring to deliver me from my perplexities by quoting passages such as these. For although no man's wishes can make that true which is not true, nevertheless, were this possible, I would wish that this opinion should be true, as I do wish that, if it is true, it should be most clearly and unanswerably vindicated by you.
Source: Letters (New Advent)