Sometimes, indeed, this lustful cruelty, or if you please, cruel lust, resorts to such extravagant methods as to use poisonous drugs to secure barrenness; or else, if unsuccessful in this, to destroy the conceived seed by some means previous to birth, preferring that its offspring should rather perish than receive vitality; or if it was advancing to life within the womb, should be slain before it was born.
-De Nube et Concupiscentia 1.17 (15)
On the undeveloped fetus:
Hence in the first place arises a question about abortive conceptions, which have indeed been born in the mother's womb, but not so born that they could be born again. For if we shall decide that these are to rise again, we cannot object to any conclusion that may be drawn in regard to those which are fully formed. Now who is there that is not rather disposed to think that unformed abortions perish, like seeds that have never fructified? But who will dare to deny, though he may not dare to affirm, that at the resurrection every defect in the form shall be supplied, and that thus the perfection which time would have brought shall not be wanting, any more than the blemishes which time did bring shall be present: so that the nature shall neither want anything suitable and in harmony with it that length of days would have added, nor be debased by the presence of anything of an opposite kind that length of days has added; but that what is not yet complete shall be completed, just as what has been injured shall be renewed.
On therapeutic abortion:
And therefore the following question may be very carefully inquired into and discussed by learned men, though I do not know whether it is in man's power to resolve it: At what time the infant begins to live in the womb: whether life exists in a latent form before it manifests itself in the motions of the living being. To deny that the young who are cut out limb by limb from the womb, lest if they were left there dead the mother should die too, have never been alive, seems too audacious. Now, from the time that a man begins to live, from that time it is possible for him to die. And if he die, wheresoever death may overtake him, I cannot discover on what principle he can be denied an interest in the resurrection of the dead.
Therefore brothers, you see how perverse they are and hastening wickedness, who are immature, they seek abortion of the conception before the birth; they are those who tell us, "I do not see that which you say must be believed."
- Sermon 126, line 12