Christianity is often called a religion. More properly it is called a "faith." We often speak of the Christian faith. It is called a faith because there is a body of knowledge that is affirmed or believed by its adherents. It is also called a faith because the virtue of faith is central to its understanding of redemption.
What does faith mean? In our culture it is often mistaken for a blind belief in something that is unreasonable. To call the Christian faith a "blind faith," however, is not only demeaning to Christians, but an outrage to God. When the Bible speaks of blindness it uses this image for people who, by their sin, walk in darkness. Christianity calls people out of the darkness, not into the darkness. Faith is the antidote to blindness, not the cause of it.
At its root, the term faith means "trust." To trust God is not an act of unreasonable belief. God demonstrates Himself to be eminently trustworthy. He gives ample reason for us to trust Him. He proves that He Himself is faithful and worthy of our trust.
There is a huge difference between faith and credulity. To be credulous is to believe something for no sound reason. It is the stuff of which superstition is made and thrives on. Faith is established upon coherent and consistent reasoning and upon sound empirical evidence. Peter writes, "For we did not follow cunningly devised fables when we made known to you the power and coming of our Lord Jesus Christ, but were eyewitnesses of His majesty" (2 Peter 1:16).
Christianity does not rest upon myths and fables but on the testimony of those who saw with their eyes and heard with their ears. The truth of the gospel is based on historical events. If the account of those events is not trustworthy, then indeed our faith would be in vain. But God does not ask us to believe anything on the basis of myth.
The book of Hebrews gives us a definition of faith: "Now faith is the substance of things hoped for, the evidence of things not seen" (Hebrews 11:1). Faith comprises the essence of our hope for the future. In simple terms this means that we trust God for the future based on our faith in what He has accomplished in the past. To believe that God will continue to be trustworthy is not a gratuitous faith. There is every reason to believe that God will be as faithful to His promises in the future as He has been in the past. There is a reason, a substantive reason, for the hope that is within us.
The faith that is the evidence of things unseen has primary but not exclusive reference to the future. Nobody has a crystal ball that works. We all walk into the future by faith and not by sight. We may plan and make projections, but even the best foresight we have is based upon our educated guesses. None of us has experiential knowledge of tomorrow. We view the present and can recall the past. We are experts in hindsight. The only solid evidence we have for our own future is drawn from the promises of God. Here faith offers evidence for things unseen. We trust God for tomorrow.
We also trust or believe that God exists. And although God Himself is unseen, the Scriptures make it clear that the invisible God is made manifest through the things that are visible (Romans 1:20). Though God is not visible to us, we believe that He is there because He has manifested Himself so clearly in creation and in history.
Faith includes believing in God. Yet that kind of faith is not particularly praiseworthy. James writes, "You believe that there is one God. You do well. Even the demons believe—and tremble!" (James 2:19). Here sarcasm drips from James's pen. To believe in the existence of God merely qualifies us to be demons. It is one thing to believe in God; it is another thing to believe God. To believe God, to trust in Him for our very life, is the essence of the Christian faith.