Why is faith necessary for spiritual or unseen things?
Faith is necessary because spiritual and unseen realities cannot be seen or tangibly touched; they must be accepted by taking God at His Word. Scripture defines faith as the substance of things hoped for and the evidence of things not seen, so the invisible realm can only be entered and depended upon by faith.
Les explains that in Romans 8, Paul says we are saved by hope, and faith and hope carry the same meaning. Hope that is seen is not hope, because what a person sees, he no longer hopes for. So when we enter the realm of the invisible, the only thing to depend on is faith. Les then points to Hebrews 11:1, where faith—taking God at His Word—is the substance of things hoped for and the evidence, or proof, of things unseen. When we enter into the spiritual realm, into things we cannot tangibly touch, it has to be on the basis of faith. Les also notes that if he did not know this was the Word of God, he could not believe it.