The fundamental fact of existence is that this trust in God, this faith, is the firm foundation under everything that makes life worth living. It's our handle on what we can't see.
The act of faith is what distinguished our ancestors, set them above the crowd.
By faith, we see the world called into existence by God's word, what we see created by what we don't see.
By an act of faith, Abel brought a better sacrifice to God than Cain. It was what he believed, not what he brought, that made the difference. That's what God noticed and approved as righteous. After all these centuries, that belief continues to catch our notice.
By an act of faith, Enoch skipped death completely. "They looked all over and couldn't find him because God had taken him." We know on the basis of reliable testimony that before he was taken "he pleased God."
It's impossible to please God apart from faith. And why? Because anyone who wants to approach God must believe both that he exists and that he cares enough to respond to those who seek him.
By faith, Noah built a ship in the middle of dry land. He was warned about something he couldn't see, and acted on what he was told. The result? His family was saved. His act of faith drew a sharp line between the evil of the unbelieving world and the rightness of the believing world. As a result, Noah became intimate with God.
By an act of faith, Abraham said yes to God's call to travel to an unknown place that would become his home. When he left he had no idea where he was going.
By an act of faith he lived in the country promised him, lived as a stranger camping in tents. Isaac and Jacob did the same, living under the same promise.
Abraham did it by keeping his eye on an unseen city with real, eternal foundations - the City designed and built by God.
By faith, barren Sarah was able to become pregnant, old woman as she was at the time, because she believed the One who made a promise would do what he said.