Hebrews 11:1 says faith is the assurance of what we hope for and the conviction of things we have not seen. Our belief (faith) determines much. The Bible teaches that unless you believe, you will: lose heart, not hear God's instructions, not be prepared for judgment. Jesus said in John 8:24, "if you do not believe that I am He, you will die in your sins." Our faith is the basis for our relationship with God.