It almost sounds as if Jesus contradicted Himself. When asked why the disciples had not been able to exorcise the demon, He said it was because of unbelief. But now He seems to be saying that it is because they had not fasted and prayed enough. Which is it?
Something amazing happened at the Cross of Calvary and what was visible to us was merely superficial. The Tree had roots back into the past eternity and its branches stretched upward into eternities to come. It was a real event in the realm of reality - infinitely more real to God, to the dimension of all angels and spirits, in heaven and hell, than what we saw. “God was in Christ reconciling the world to Himself.” (2 Corinthians 5:19)
I think many of God’s people don’t realise how sinister and dangerous unbelief is. Many pious and self-righteous Christians look down their religious noses at people committing other, more visible sins.
Not seeing is no reason for not believing. Nobody sees radiation. We wait for its effects. Nobody sees God, but millions find the effects in their lives. Unexpected and miraculous things sometimes happen—things that can only be from Him.