Genesis 21:1-8 New Revised Standard Version (NRSV)
The Birth of Isaac
21 The Lord dealt with Sarah as he had said, and the Lord did for Sarah as he had promised. 2 Sarah conceived and bore Abraham a son in his old age, at the time of which God had spoken to him. 3 Abraham gave the name Isaac to his son whom Sarah bore him. 4 And Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. 5 Abraham was a hundred years old when his son Isaac was born to him. 6 Now Sarah said, “God has brought laughter for me; everyone who hears will laugh with me.” 7 And she said, “Who would ever have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.”
Hagar and Ishmael Sent Away
8 The child grew, and was weaned; and Abraham made a great feast on the day that Isaac was weaned.