Hebrews 11:1-4

Now faith is the assurance of things hoped for, the conviction of things not seen. For by it the men of old gained approval. By faith we understand that the worlds were prepared by the word of God, so that what is seen was not made out of things which are visible. By faith Abel offered to God a better sacrifice than Cain, through which he obtained the testimony that he was righteous, God testifying about his gifts, and through faith, though he is dead, he still speaks.