The impossible happens. Sarah bears a son at ninety, and Abraham is a hundred. They name him Isaac — laughter — as God commanded. He is circumcised on the eighth day. The feast at his weaning fractures the household: Sarah sees Ishmael 'mocking,' demands Hagar and Ishmael be expelled, and Abraham is distressed. God tells him to listen to Sarah. Hagar and Ishmael go into the wilderness of Beer-sheba, and when the water runs out, God hears the child crying.