God fulfills his promise. Sarah conceives and bears Abraham a son at the exact time that God had told them. They name him Isaac.

Abraham circumcises his son when he is eight years old. This, he did, in accordance with the command God gave him. Abraham is 100 years of age now. Sarah is excited. God has given her a cause to laugh, she feels. Sarah is now convinced that all those who hear this will her will rejoice with her; now that she has born a son to Abraham in his old age.

Isaac grows up and is weaned. Abraham gives a great banquet on that day.

Sarah now watches her son playing with Ishmael. He is the son of Hagar, the Egyptian slave Sarah had given Abraham. She wants him to drive away Hagar with her son. He should not share the inheritance with Isaac, Sarah feels.

This hurts Abraham; Ishmael too is his son. But God comes to his rescue. He commands Abraham to do as Sarah told her. It is Isaac who will carry the name of Abraham. God will also make Ishmael a great nation because he too is the son of Abraham.