Matthew 17: 20
And Jesus said unto them, Because of your unbelief: for verily say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.
Now faith is the substance of things hoped for, the evidence of things not seen.
2 Corinthians 5:7
For we walk by faith, not by sight.