In Chapter 21, we find the fulfillment of God’s promise: the birth of Isaac. Because of Sarah’s complaint, Hagar and Ishmael are cast out to wander the wilderness. Although Isaac is confirmed as the heir of Abraham, God does not abandon Hagar and Ishmael. Abraham makes a covenant with a local ruler named Abimelech at Beersheba.
God kept His promise; Abraham and Sarah conceive and have a son at the appointed time. Abraham names the boy Isaac and circumcises him at eight days old in obedience to God.
Abraham was 100 years old when Isaac was born. Sarah was very happy at Isaac’s birth. Isaac grew, and a feast was given when he was weaned.
Sarah wants Abraham’s son, Ishmael, sent away from their house. She wants her own son, Isaac, to be the sole heir of Abraham. Abraham worries what will become of Ishmael, but God promises that a nation will be born from Ishmael.
Abraham sends Hagar and Ishmael away. They wander in the wilderness and run out of water. Hagar thinks they will die, but God hears Ishmael’s cries and rescues them.
God assures Hagar that Ishmael will live and make a great nation. Miraculously, God leads them to a well to drink. Ishmael grows up, becomes an archer, and marries an Egyptian woman.
King Abimelech knows that God favors Abraham, so he makes a covenant with him, asking for fair and honest dealing. Abraham agrees.
Abraham complains that Abimelech’s men have taken over his well. Abimelech claims he had not heard of this well until today. Abraham sets apart seven lambs for Abimelech to give the well rights back to him.
Abraham names the place where he made an oath with Abimelech, “Beersheba.” After the covenant is made, Abraham plants a tree at Beersheba and prays to God.