This post was originally written in June 2017. To navigate back to the Genesis index, see index-genesis.
As the text of the Hebrew Bible stands today, Abraham is Isaac’s father. And yet.
The Pentateuch, as has been widely recognized at least since the days of Wellhausen, is like a suit jacket. It functions as a single article of clothing, but here and there are seams — spots where one can see that the thing was not created from a single piece of cloth, but stitched together from multiple sources. Whether or not you buy the model of its history that says it was stitched together from well-identified sources commonly known as J, E, D, and P, the seams are there. They testify to a complex prehistory, in which some of the stories existed prior to being edited into a whole.
That prehistory is contested. We don’t have the pre-Pentateuch texts used in building it. So we are left, in many cases, with a bunch of unprovable hypotheses, some better founded than others. I wouldn’t claim any particular skill at reconstructing the prehistory of the text, but here and there I see things that make me wonder.
According to Genesis, Abraham and Sarah find themselves unable to have children. Three men arrive in Genesis 18, when Abraham is 99 and Sarah 89, announcing that she will soon give birth to a son. In Genesis 21, when Abraham is 100 and Sarah 90, Sarah has a boy named Isaac.
In after the events of 18, and immediately preceding chapter 21, chapter 20 relates a curious tale, in which Sarah is taken into the harem of a king named Abimelech. Abimelech even gives a massive financial compensation to Abraham after he learns that Sarah was, in fact, already a married woman. Immediately after her release, the text tells us that Sarah, finally becoming pregnant, gives birth to Isaac.
After at least twenty-five years with Abraham, producing not a single child, Sarah is taken by a foreign king and has a baby immediately thereafter. The timing is strange. And the chronological notes in chapters 18 and 21 narrow the possible time for the events of 20 to the exact year when we know Sarah became pregnant. It does not allow for any great deal of time to pass between the captivity of Sarah and her conception.
Now, the story — as it currently stands — takes pains to say that no sexual intercourse occurred between Abraham and Sarah. In 20:6, the narrator tells us that God himself acknowledges, in a dream, that Abimelech has not touched Sarah. And in 25:19, Genesis explicitly tells us that Abraham is the father.
But imagine that you are one of Abraham’s contemporaries. What would you assume? Or imagine that you were someone who thought that Genesis had an extensive prehistory before being edited into its final shape. What would you think of the strange placement of the Abimelech episode?
Interestingly, Rashi picked up on this. In his note on 25:19, he says that the words in 25:19 are there to indicate that God proved Isaac’s paternity, because “scorners” were saying that Abimelech was Isaac’s father.