Genesis 21:1-7

21:1 The Lord visited Sarah just as he had said he would and did for Sarah what he had promised. 2 So Sarah became pregnant and bore Abraham a son in his old age at the appointed time that God had told him. 3 Abraham named his son—whom Sarah bore to him—Isaac. 4 When his son Isaac was eight days old, Abraham circumcised him just as God had commanded him to do. 5 (Now Abraham was one hundred years old when his son Isaac was born to him.)

6 Sarah said, “God has made me laugh. Everyone who hears about this will laugh with me.” 7 She went on to say, “Who would have said to Abraham that Sarah would nurse children? Yet I have given birth to a son for him in his old age!”