Genesis 20:8-18
Isaac’s Birth
Genesis 21:1-7
God’s Promise Fulfilled and Sarah’s Tenuous Belief
Sarah’s laughter can be understood in two ways.
- At first her laughter seems to be a celebration of God’s generosity toward her (“Elohim has made laughter for me!”).
- But, like Avraham, laughter can be a response of unbelief, as if she simply can’t believe that this was the work of Yahweh to fulfill the covenant promise. Thus her question, “Who would have told …” seems to be more than simply rhetorical. The obvious answer to her question is “God told you!” Sarah’s laughter seems to indicate an abiding lack of trust in the promise of God.
Yitskhaq, Circumcision, and Echoes of Noah’s Obedience
This unit is riddled with allusions to the flood narrative and to Genesis 17, an earlier Avraham narrative that also echoed the flood narrative. Avraham is obedient to the divine command given in Genesis 17:9-14 that everyone in his family should be circumcised as a sign of God’s covenant with them.
1. In the flood story, God’s promise of a coming flood (hammabbul / לובמה) was fulfilled, and God commanded Noah to build and board the ark to keep his family and the animals alive. The fulfillment of and the obedience to the divine word are both registered in the narrative.
2. In Avraham’s story, God’s promise of a coming son was fulfilled, and God commands Avraham to give his son a specific name and to circumcise (himmol / לומה) him. Both fulfillments and the obedience to the divine command are registered in the narrative.
In this way, Yitskhaq’s arrival and his circumcision strike the note of the flood narrative and mark this unit as a hinge narrative that concludes the thematic cycle and also begins a new thematic cycle.
These stories are deeply interested in tracing cause and effect sequences over long periods of time and across generations, as well as how the sins of the parents affect their children. —Tim Mackie, The Bible Project