211 Now YHWH singled out Sarah and carried out just what YHWH had promised her. 2 Sarah conceived and bore a son to Abraham in his old age, at the set-time God had told him. 3 Abraham named his son, the one Sarah bore him, Isaac. 4 Abraham circumcised his son Isaac when he was eight days old, just as God had charged him. 5 Abraham was a hundred years old when his son Isaac was born. 6 Sarah said, “God has made laughter for me. Everyone who hears about it will laugh at me.” 7 She said, “Who could have told Abraham that Sarah would nurse sons? Well, I’ve borne him a son in his old age!”
For Sarah’s sake, all the wombs of Abimelech’s kingdom had been closed. Now, for Sarah’s sake, she has been singled out to have her womb finally opened at the ripe age of ninety. Of course, the background of this attention is the fulfillment of a promise to Abraham. Before hearing from Sarah, it is noted that Abraham names the boy Isaac (Laughter) and circumcises him on his eighth day of life. The eight days echo a first creation of six days and a Sabbath and an additional day for now being in a next creation after a flood.
With this personal and tribal myth actions completed, we turn to hear Sarah reflecting on the ambiguity of her situation of having a new baby suckling at old dugs. There is an unbridled joy here as well as a primal joke by an ancient-of-days coyote leaving discomfiture in his wake.
The Hebrew for laughter is here followed by an indeterminate preposition. Readers will need to decide whether Sarah means that whosoever hears this tale will laugh to hear of it or laugh for joy or laugh with Sarah or laugh at
Sarah seems to favor the absurdist view as she remarks, “Who in their right mind would have ever thought they would say, ‘Sarah’s nursing!’”
With a recognition that, whether it makes any sense or not, the promise to Abraham many years prior in Haran that Abraham would begin a great nation is now underway. The first piece is in place after a series of risks to Sarah with Pharaoh and Abimelech and Abraham warring to save Lot and worn out with covenant services and seemingly in-vain promises.