Genesis 15:2-5

2But Abram said, “Lord God, what can you give me, since I am childless and the heir of my house is Eliezer of Damascus?”

3Abram continued, “Look, you have given me no offspring, so a slave born in my house will be my heir.”

4Now the word of the Lord came to him: “This one will not be your heir; instead, one who comes from your own body will be your heir.”

5He took him outside and said, “Look at the sky and count the stars, if you are able to count them.” Then he said to him, “Your offspring will be that numerous.”