Genesis 15:2-5

But Abram said, “Lord GOD, what can you give me? I have no son, so my slave Eliezer from Damascus will get everything I own after I die.” Abram said, “Look, you have given me no son, so a slave born in my house will inherit everything I have.” Then the LORD spoke his word to Abram: “He will not be the one to inherit what you have. You will have a son of your own who will inherit what you have.” Then God led Abram outside and said, “Look at the sky. There are so many stars you cannot count them. Your descendants also will be too many to count.”