The City of God

is thy seed.”936 How then is it said, “In Isaac shall thy seed be called,” when God calls Ishmael also his seed? The apostle, in explaining this, says, “In Isaac shall thy seed be called, that is, they which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.”937 In order, then, that the children of the promise may be the seed of Abraham, they are called in Isaac, that is, are gathered together in Christ by the call of grace. Therefore the father, holding fast from the first the promise which behoved to be fulfilled through this son whom God had ordered him to slay, did not doubt that he whom he once thought it hopeless he should ever receive would be restored to him when he had offered him up. It is in this way the passage in the Epistle to the Hebrews is also to be understood and explained. “By faith,” he says, “Abraham overcame, when tempted about Isaac: and he who had received the promise offered up his only son, to whom it was said, In Isaac shall thy seed be called: thinking that God was able to raise him up, even from the dead”; therefore he has added, “from whence also he received him in a similitude.”938 In whose similitude but His of whom the apostle says, “He that spared not His own Son, but delivered Him up for us all?”939 And on this account Isaac also himself carried to the place of sacrifice the wood on which he was to be offered up, just as the Lord Himself carried His own cross. Finally, since Isaac was not to be slain, after his father was forbidden to smite him, who was that ram by the offering of which that sacrifice was completed with typical blood? For when Abraham saw him, he was caught by the horns in a thicket. What, then, did he represent but Jesus, who, before He was offered up, was crowned with thorns by the Jews?

But let us rather hear the divine words spoken through the angel. For the Scripture says, “And Abraham stretched forth his hand to take the knife, that he might slay his son. And the Angel of the Lord called unto him from heaven, and said, Abraham. And he said, Here am I. And he said, Lay not thine hand upon the lad, neither do thou anything unto him: for now I know that thou fearest God, and hast not spared thy beloved son for my sake.”940 It is said, “Now I know,” that is, Now I have made to be known; for God was not previously ignorant of this. Then, having offered up that ram instead of Isaac his son, “Abraham,” as we read, “called the name of that place The Lord seeth: as they say this day, In the mount the Lord hath appeared.”941 As it is said, “Now I know,” for Now I have made to be known, so here, “The Lord sees,” for The Lord hath appeared, that is, made Himself to be seen. “And the Angel of the Lord called unto Abraham from heaven the second time, saying, By myself have I sworn, saith the Lord; because thou hast done this thing, and hast not spared thy beloved son for my sake; that in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of heaven, and as the sand which is upon the seashore; and thy seed shall possess by inheritance the cities of the adversaries: and in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.”942 In this manner is that promise concerning the calling of the nations in the seed of Abraham confirmed even by the oath of God, after that burnt-offering which typified Christ. For He had often promised, but never sworn. And what is the oath of God, the true and faithful, but a confirmation of the promise, and a certain reproof to the unbelieving?

After these things Sarah died, in the 127th year of her life, and the 137th of her husband; for he was ten years older than she, as he himself says, when a son is promised to him by her: “Shall a son be born to me that am an hundred years old? and shall Sarah, that is ninety years old, bear?”943 Then Abraham bought a field, in which he buried his wife. And then, according to Stephen’s account, he was settled in that land, entering then on actual possession of it⁠—that is, after the death of his father, who is inferred to have died two years before.

XXXIII

Of Rebecca, the granddaughter of Nahor, whom Isaac took to wife.

Isaac married Rebecca, the granddaughter of Nahor, his father’s brother, when he was forty years old, that is, in the 140th year of his father’s life, three years after his mother’s death. Now when a servant was sent to Mesopotamia by his father to fetch her, and when Abraham said to that servant, “Put thy hand under my thigh, and I will make thee swear by the Lord, the God of heaven, and the Lord of the earth, that thou shalt not take a wife unto my son Isaac of the daughters of the Canaanites,”944 what else was pointed out by this, but that the Lord, the God of heaven, and the Lord of the earth, was to come in the flesh which was to be derived from that thigh? Are these small tokens of the foretold truth which we see fulfilled in Christ?

XXXIV

What is meant by Abraham’s marrying Keturah after Sarah’s death.

What did Abraham mean by marrying Keturah after Sarah’s death? Far