Genesis 15:1-2, 8

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.

But Abram replied, “O Sovereign LORD, how can I be sure that I will actually possess it?”