Sometimes the happiest day in one part of a family is the worst in another. A long-awaited baby arrives, the relatives celebrate — and someone on the edge of the household realises there is no longer a place for them. Genesis 21 holds both at once. After twenty-five years of waiting, Sarah gives birth, and the house is full of laughter. A few years later, at the feast for Isaac's weaning, that laughter turns sour, and a mother and her teenage son are sent into the desert with bread and a skin of water.
Where it sits in the story: The promise of a son, made in Genesis 12 and repeated ever since, is finally kept: Isaac is born exactly as God said. Yet the story refuses a simple happy ending. Ishmael is cast out, and God again meets Hagar in the wilderness, keeping his separate promise to make him a nation. The chapter closes with Abraham making a treaty at Beersheba — a first small legal foothold in the promised land. Islam honours Hagar and Ishmael, and remembers her search for water in the Hajj.
What this chapter is doing: To show God keeping his promise in Isaac's birth, while also caring for Ishmael and Hagar, and to give Abraham a first secure right to a well in the land.
- 21:1–7 — The LORD does for Sarah exactly what he promised. Abraham, now one hundred, names the boy Isaac — 'he laughs' — and circumcises him on the eighth day. Sarah says God has brought her laughter, and everyone who hears will laugh with her.
- 21:8–13 — At the weaning feast Sarah sees Ishmael laughing — the word can mean playing or mocking — and demands that Abraham send Hagar and her son away. Abraham is deeply distressed, but God tells him to listen: Isaac carries the promise, and Ishmael too will become a nation.
- 21:14–21 — Hagar wanders in the wilderness of Beersheba until the water runs out, then sets the boy under a bush and sits at a distance so as not to watch him die. God hears the boy's voice, opens her eyes to a well, and stays with Ishmael as he grows into an archer in the wilderness of Paran.
- 21:22–34 — Abimelech and his commander Phicol seek a treaty with Abraham. After a dispute over a seized well, Abraham gives seven ewe lambs as witness that he dug it. The place is named Beersheba, and Abraham plants a tamarisk and calls on the Everlasting God.
- Updated name: a later writer or editor used the name familiar to his readers for the region, as we might speak of 'India' for an earlier age.
- Earlier group: some argue for earlier Aegean-linked settlers in the area whom the text calls by the later name.
- Later composition: many critical scholars see it as one sign that the stories took their present form long after the setting they describe.
Key verse: Genesis 21:17 · So what: The chapter does not tidy the pain away. The promised child is born, and another child is sent out, and God is present in both places. For readers of different faiths who trace their story to Abraham, it is a reminder that God heard the cry of the one who was sent away.