Genesis 20:17

Unless Sarah received renewed youth in the seed that she had received, Abim-elech would not have desired a woman ninety years old. Then Abraham prayed and God healed Abimelech, his wife and his female slaves so that they bore children, because from the time [Abim-elech] had decided to marry Sarah until he returned her, pangs of childbirth struck all the women in his household; they would kneel down, but they could not give birth.

But it does not seem to me pointless that mention is made not only of Abimelech's wife but also of his female servants, especially in this, that it says: "God healed them and they were bearing children. For he had closed them up, that they should not bear." As far as we are able to perceive in such difficult passages, we suppose that Abimelech's wife can be called natural philosophy, but his maidservants the diverse and varied inventions of dialectic according to the character of the several schools. Meanwhile Abraham desires to impart the gift of divine power even to the nations, but the time has not yet come for the grace of God to pass over from the former people to the nations. For the Apostle too, though under another guise and another figure, nevertheless says: "that a woman is bound to the law as long as her husband lives; but if her husband is dead, she is freed from the law, so that she is no longer an adulteress if she be with another man." Therefore the law of the letter must first die, so that at last the soul, now free, may wed the spirit and obtain the marriage of the new testament. But this present time, in which we now are, is the time of the calling of the nations and of the death of the law, in which free souls, now released from the law of the husband, may wed a new husband, Christ. But if you wish to be taught how the law is dead, consider and see: where now are the sacrifices, where now the altar, where the temple, where the purifications, where the solemn feast of the Passover? Is not the law dead in all these things? Or, if these friends and defenders of the letter are able, let them keep the letter of the law. According to this order of allegory, then, Pharaoh, who is an unclean man and a destroyer, could by no means receive Sarah, that is, virtue. Further, Abimelech, that is, one who lived purely and philosophically, could indeed receive her, because he sought "with a pure heart," but "the time had not yet come." Virtue therefore remains with Abraham, remains in circumcision, until the time comes when, in Christ Jesus our Lord, in whom "dwells all the fullness of the deity bodily," whole and perfect virtue may pass over to the Church of the nations. Then, therefore, both the house of Abimelech and his maidservants, whom the Lord healed, will bear children for the Church. For this is the time in which "the barren woman" bears, and in…