Genesis
1 And when Abram was ninty years old and nine, the LORD appeared to Abram, and said unto him, I am the Almighty God; walk before me, and be thou perfect.
2 And I will make my covenant between me and thee, and will multiply thee exceedingly.
3 And Abram fell on his face: and GOD talked with him, saying,
4 As for me, behold, my covenant is with thee, and thou shalt be a father of many nations.
5 Neither shall thy name any maore be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.
15 And GOD said unto Abraham, as for Sa'-rai thy wife, thou shalt not call her name Sa'-rai, but Sa-rah shall her name be.
God made a covenant between HIM and Abraham and promised to establish that covenant forever. And GOD blessed Abraham and Sarah to be a father and mother of nations.