Genesis 17:1-7 New Revised Standard Version (NRSV)
The Sign of the Covenant
17 When Abram was ninety-nine years old, the Lord appeared to Abram, and said to him, “I am God Almighty;[a] walk before me, and be blameless. 2 And I will make my covenant between me and you, and will make you exceedingly numerous.” 3 Then Abram fell on his face; and God said to him, 4 “As for me, this is my covenant with you: You shall be the ancestor of a multitude of nations. 5 No longer shall your name be Abram,[b] but your name shall be Abraham;[c] for I have made you the ancestor of a multitude of nations. 6 I will make you exceedingly fruitful; and I will make nations of you, and kings shall come from you. 7 I will establish my covenant between me and you, and your offspring after you throughout their generations, for an everlasting covenant, to be God to you and to your offspring[d] after you.
Genesis 17:15-19 New Revised Standard Version (NRSV)
15 God said to Abraham, “As for Sarai your wife, you shall not call her Sarai, but Sarah shall be her name. 16 I will bless her, and moreover I will give you a son by her. I will bless her, and she shall give rise to nations; kings of peoples shall come from her.” 17 Then Abraham fell on his face and laughed, and said to himself, “Can a child be born to a man who is a hundred years old? Can Sarah, who is ninety years old, bear a child?” 18 And Abraham said to God, “O that Ishmael might live in your sight!” 19 God said, “No, but your wife Sarah shall bear you a son, and you shall name him Isaac.[a] I will establish my covenant with him as an everlasting covenant for his offspring after him.