There is no specific definition of faith given in the Scriptures. But the Book of Hebrews describes faith: “Now faith is the substance of things hoped for, the evidence of things not seen” (Hebrews 11:1).
Substance means “solid ground.” The English word “substance” gives the meaning of the Greek word “hupostasis.” It means there is something beneath us to stand upon. When we are living by faith, we are standing upon the solid rock. Sometimes the materialist will say, “Don’t talk to me about faith. Talk about real things.” He means, of course, the things that can be experienced with the five senses—the things we can see, smell, hear, taste, or touch.
But are these the only things that are real? Paul reminded us that “the things which are seen are temporary; but the things which are not seen are eternal” (2 Corinthians 4:18). Which is more real—that which is temporary or that which is eternal? Which is more substantial? Which is able to support you? Where will you stand?
This means that faith is convincing proof that God will keep His Word. Evidence is proof of unseen reality. There can be no evidence without the reality that gave rise to the evidence. If we understand this, we shall see the difference between real faith, based on the truth of God’s Word, and synthetic faith, based on wishful thinking.
The prophets of this synthetic faith say, “If you have enough faith, God will do anything for you. All you have to do is name it and claim it.” That sounds good, but it bears little resemblance to biblical faith. We cannot legitimately claim it until God has named it. Faith is our response to a revelation of God’s will by His Word and His Spirit. “So then faith comes by hearing, and hearing by the word of God” (Romans 10:17).
Faith is the evidence in our hearts that God has spoken, and He will act according to His Word.