Genesis 15:1-4

Some time later, the LORD spoke to Abram in a vision and said to him, “Do not be afraid, Abram, for I will protect you, and your reward will be great.” But Abram replied, “O Sovereign LORD, what good are all your blessings when I don’t even have a son? Since you’ve given me no children, Eliezer of Damascus, a servant in my household, will inherit all my wealth. You have given me no descendants of my own, so one of my servants will be my heir.” Then the LORD said to him, “No, your servant will not be your heir, for you will have a son of your own who will be your heir.”