City of God, Book XVI
Chapter 28.—Of the Change of Name in Abraham and Sarah, Who Received the Gift of Fecundity When They Were Incapable of Regeneration Owing to the Barrenness of One, and the Old Age of Both.
Now when a promise so great and clear was made to Abraham, in which it was so plainly said to him, “I have made thee a father of many nations, and I will increase thee exceedingly, and I will make nations of thee, and kings shall go forth of thee. And I will give thee a son of Sarah; and I will bless him, and he shall become nations, and kings of nations shall be of him,” —a promise which we now see fulfilled in Christ,—from that time forward this couple are not called in Scripture, as formerly, Abram and Sarai, but Abraham and Sarah, as we have called them from the first, for every one does so now. The reason why the name of Abraham was changed is given: “For,” He says, “I have made thee a father of many nations.” This, then, is to be understood to be the meaning of Abraham; but Abram, as he was formerly called, means “exalted father.” The reason of the change of Sarah’s name is not given; but as those say who have written interpretations of the Hebrew names contained in these books, Sarah means “my princess,” and Sarai “strength.” Whence it is written in the Epistle to the Hebrews, “Through faith also Sarah herself received strength to conceive seed.” For both were old, as the Scripture testifies; but she was also barren, and had ceased to menstruate, so that she could no longer bear children even if she had not been barren. Further, if a woman is advanced in years, yet still retains the custom of women, she can bear children to a young man, but not to an old man, although that same old man can beget, but only of a young woman; as after Sarah’s death Abraham could of Keturah, because he met with her in her lively age. This, then, is what the apostle mentions as wonderful, saying, besides, that Abraham’s body was now dead; because at that age he was no longer able to beget children of any woman who retained now only a small part of her natural vigor. Of course we must understand that his body was dead only to some purposes, not to all; for if it was so to all, it would no longer be the aged body of a living man, but the corpse of a dead one.
Although that question, how Abraham begot children of Keturah, is usually solved in this way, that the gift of begetting which he received from the Lord, remained even after the death of his wife, yet I think that solution of the question which I have followed is preferable, because, although in our days an old man of a hundred years can beget children of no woman, it was not so then, when men still lived so long that a hundred years did not yet bring on them the decrepitude of old age.
Chapter 29.—Of the Three Men or Angels, in Whom the Lord is Related to Have Appeared to Abraham at the Oak of Mamre.
God appeared again to Abraham at the oak of Mamre in three men, who it is not to be doubted were angels, although some think that one of them was Christ, and assert that He was visible before He put on flesh. Now it belongs to the divine power, and invisible, incorporeal, and incommutable nature, without changing itself at all, to appear even to mortal men, not by what it is, but by what is subject to it. And what is not subject to it? Yet if they try to establish that one of these three was Christ by the fact that, although he saw three, he addressed the Lord in the singular, as it is written, “And, lo, three men stood by him: and, when he saw them, he ran to meet them from the tent-door, and worshipped toward the ground, and said, Lord, if I have found favor before thee,” etc.; why do they not advert to this also, that when two of them came to destroy the Sodomites, while Abraham still spoke to one, calling him Lord, and interceding that he would not destroy the righteous along with the wicked in Sodom, Lot received these two in such a way that he too in his conversation with them addressed the Lord in the singular? For after saying to them in the plural, “Behold, my lords, turn aside into your servant’s house,” etc., yet it is afterwards said, “And the angels laid hold upon his hand, and the hand of his wife, and the hands of his two daughters, because the Lord was merciful unto him. And it came to pass, whenever they had led him forth abroad, that they said, Save thy life; look not behind thee, neither stay thou in all this region: save thyself in the mountain, lest thou be caught. And Lot said unto them, I pray thee, Lord, since thy servant hath found grace in thy sight,” etc. And then after these words the Lord also answered him in the singular, although He was in two angels, saying, “See, I have accepted thy face,” etc.
This makes it much more credible that both Abraham in the three men and Lot in the two recognized the Lord, addressing Him in the singular number, even when they were addressing men; for they received them as they did for no other reason than that they might minister human refection to them as men who needed it. Yet there was about them something so excellent, that those who showed them hospitality as men could not doubt that God was in them as He was wont to be in the prophets, and therefore sometimes addressed them in the plural, and sometimes God in them in the singular. But that they were angels the Scripture testifies, not only in this book of Genesis, in which these transactions are related, but also in the Epistle to the Hebrews, where in praising hospitality it is said, “For thereby some have entertained angels unawares.” By these three men, then, when a son Isaac was again promised to Abraham by Sarah, such a divine oracle was also given that it was said, “Abraham shall become a great and numerous nation, and all the nations of the earth shall be blessed in him.” And here these two things, are promised with the utmost brevity and fullness,—the nation of Israel according to the flesh, and all nations according to faith.
Chapter 30.—Of Lot’s Deliverance from Sodom, and Its Consumption by Fire from Heaven; And of Abimelech, Whose Lust Could Not Harm Sarah’s Chastity.
After this promise Lot was delivered out of Sodom, and a fiery rain from heaven turned into ashes that whole region of the impious city, where custom had made sodomy as prevalent as laws have elsewhere made other kinds of wickedness. But this punishment of theirs was a specimen of the divine judgment to come. For what is meant by the angels forbidding those who were delivered to look back, but that we are not to look back in heart to the old life which, being regenerated through grace, we have put off, if we think to escape the last judgment? Lot’s wife, indeed, when she looked back, remained, and, being turned into salt, furnished to believing men a condiment by which to savor somewhat the warning to be drawn from that example. Then Abraham did again at Gerar, with Abimelech the king of that city, what he had done in Egypt about his wife, and received her back untouched in the same way. On this occasion, when the king rebuked Abraham for not saying she was his wife, and calling her his sister, he explained what he had been afraid of, and added this further, “And yet indeed she is my sister by the father’s side, but not by the mother’s; for she was Abraham’s sister by his own father, and so near of kin. But her beauty was so great, that even at that advanced age she could be fallen in love with.”