It's easy to believe in things we can see. Our eyes tell us it's true. But what about when you are challenged to believe in something you don't see? That is FAITH by definition.
Hebrew 11:1, Now faith is confidence in what we hope for and assurance about what we do not see."
2 Corinthians 4:18, "So we fix our eyes not on what is seen, but on what is unseen, since what is seen is temporary, but what is unseen is eternal."