Genesis 18:1-15
Yahweh comes to the door of Abraham's tent at midday and eats a meal of fine flour cakes and curds under a tree. The Hebrew names the visitor singular; the eyes see three men; the speaker is Yahweh; two leave for Sodom as angels. Sarah laughs inside the tent and the divine voice draws the laugh into the open. The vocabulary of her cakes is the vocabulary of the altar that does not yet exist; the formula of her birth-promise is the formula Elisha will speak to the Shunammite; her inner question about pleasure (ednah) is preserved by the Hebrew and erased by the Greek. At Mamre God comes to a domestic table and names the time of Isaac's life.
Genesis 17:15-27
Same theophany, second petuchah. Gen 17:15-27 names what Gen 17:1-14 inscribed. Sarai becomes Sarah; Abraham laughs inwardly at the announcement and the child is named for the laugh; God says aval - truly - and the covenant narrows from Abraham's seed generally to one named son not yet conceived. Ishmael receives the creation-mandate blessing every nation can receive; Isaac receives the berit olam. At Mamre the angel will quote this annunciation back: shall a word be impossible with God? Luke quotes the angel back over Mary. The child's name is the disbelief converted into gift, and the seed-bearer is the woman God blesses by name.
Genesis 17:1-14
After thirteen years of silence following Ishmael, Yahweh appears to Abram at ninety-nine and names himself by a name the older Greek witness will quietly suppress. He commands the walk that Noah walked, gives the sign that the rainbow gave, and inscribes the covenant into flesh. Gen 17 is where the canon places its closed set of two: the bow in the cloud and the cut in the body — the only two covenant-signs Scripture designates with the precise formula ot berit. The article reports what the text says before tracing how heart-circumcision and the eighth day carry the chapter forward across six centuries to Paul.