Genesis 17

Thirteen years after Ishmael's birth, God appears to 99-year-old Abram, changing his name to Abraham (""father of a multitude"") and Sarai’s name to Sarah (""princess""). God confirms the everlasting nature of the covenant. The sign of this covenant is established as circumcision, to be performed on every male descendant as a physical mark of being set apart for God. Abraham immediately obeys, circumcising himself, his son Ishmael, and every male in his household, demonstrating faith in God's promises.