Genesis 15:1-4

After these things the word of the LORD came to Abram in a vision: “Fear not, Abram, I am your shield; your reward shall be very great.” But Abram said, “O Lord GOD, what will you give me, for I continue childless, and the heir of my house is Eliezer of Damascus?” And Abram said, “Behold, you have given me no offspring, and a member of my household will be my heir.” And behold, the word of the LORD came to him: “This man shall not be your heir; your very own son shall be your heir.”