Genesis 21:1-7

YAHWEH visited Sarah, just as he said he would, and fulfilled his promise to her. And Sarah conceived and bore Abraham a son in his old age, at the exact time God had promised them. Abraham named his son Isaac, the miracle son, whom Sarah bore him. When Isaac was eight days old, Abraham circumcised him, as God had commanded him. Abraham was one hundred years old when his son Isaac was born. Sarah said, “God has brought me laughter, and everyone who hears about this will laugh with me.” And she added, “Who would ever have told Abraham that Sarah would one day nurse children! Even though Abraham is an old man, look—I have given him a son!”