Bible Synapse
Was Abraham past fathering children when Isaac was born?
Hard question · Creation, the flood and the patriarchs · raised by 2 of the lists sceptics circulate
See the passages joined in the interactive mapThe passages
At ninety-nine Abraham laughs at the thought of a son born to a man of a hundred and to Sarah at ninety.
Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?
Abraham did not dwell on “his own body now dead”, at about a hundred years old, or on Sarah’s barren womb.
And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sara’s womb:
From one man, “and him as good as dead”, came descendants as many as the stars.
Through faith also Sara herself received strength to conceive seed, and was delivered of a child when she was past age, because she judged him faithful who had promised. Therefore sprang there even of one, and him as good as dead, so many as the stars of the sky in multitude, and as the sand which is by the sea shore innumerable.
Abraham takes another wife, Keturah, who bears him six sons.
Then again Abraham took a wife, and her name was Keturah. And she bare him Zimran, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah.
Abraham lives to the age of 175.
And these are the days of the years of Abraham’s life which he lived, an hundred threescore and fifteen years.
The objection
Paul says Abraham’s body was “now dead” at about a hundred years old, and Hebrews calls him “as good as dead” (Romans 4:19; Hebrews 11:12). Yet after Sarah died he married Keturah and fathered six more sons (Genesis 25:1–2). If he could father six sons later, why was Isaac’s birth a miracle?
The answer
Romans and Hebrews describe Abraham as he was when God promised Isaac, and Genesis agrees with them. At ninety-nine he laughed at the idea: “Shall a child be born unto him that is an hundred years old?” (Genesis 17:17), and Sarah was long past bearing (18:11). Isaac’s birth was God’s doing, and both writers stress it to show the strength of Abraham’s faith.
Genesis 25 does not undo this; it shows that what God gave lasted. Genesis tells of his marriage to Keturah after Sarah’s death, when Abraham was at least 137 (Genesis 21:5; 23:1). Many, Calvin and Matthew Henry among them, have held that God’s renewal of Abraham’s strength did not end with Isaac’s birth but stayed with him for the rest of his life; Augustine reports this as the usual answer in his day. Abraham lived to 175 (Genesis 25:7), and a man whom God had renewed at a hundred could father children decades later. Paul’s point stands: at a hundred, left to nature, it could not be done.
Other answers Christians give
A younger wife
Paul sets Abraham’s body beside “the deadness of Sara’s womb” (Romans 4:19): what nature could not give was a child to the two of them. Keturah was presumably much younger than Sarah. Augustine preferred this answer: Abraham’s body was ‘dead’ for fathering a child by a woman of Sarah’s age, but not by a young wife (The City of God 16.28).
Keturah taken earlier
Calvin thought Abraham may have taken Keturah as a secondary wife while Sarah was still alive, and that Genesis 25 records this out of order; 1 Chronicles 1:32 calls her Abraham’s concubine. He still held that God had renewed Abraham’s strength for the rest of his life.
Still open
Christian writers have differed since Augustine’s day over which of these explanations is best. All of them agree with Paul that Isaac’s birth was beyond what nature could do.
From the classic commentators
The strength he received by the promise still remained in him, to show how much the virtue of the promise exceeds the power of nature.Matthew Henry, Commentary on the Whole Bible, on Genesis 25:1–4
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 preferableAugustine, The City of God, book 16, chapter 28 (tr. Marcus Dods)