Romans 4:17
As it is written: “I have made you a father of many nations.” He is our father in the sight of God, in whom he believed—the God who gives life to the dead and calls into being things that were not.

Abraham didn't even have one son, and yet God had told him that his seed would be as numerous as the stars. That must have seemed impossible to Abraham. Yet, when we look back today, we see that God indeed kept His promise. How many times has God promised US things, and we think, "Oh, that's simply not possible, that's 'unrealistic' to expect," or something like that. We need to have Abrahamic faith! When Abraham looked around, his situation looked hopeless, and it seemed like an impossibility for God to fulfill His promise. But, God always comes through. He is faithful. See things today through the eyes of faith as Abraham did.