1 - Seeing is Believing - More accurate is Believing is Seeing!!
2- For natural things, the natural eye is sufficient; but, as the natural man understandeth not the things of the Spirit of God, seeing that they are spiritual, and must be spiritually discerned, so the natural eye discerns not spiritual things.
C. H. Spurgeon, “Eyes Opened,” in The Metropolitan Tabernacle Pulpit Sermons, vol. 54 (London: Passmore & Alabaster, 1908), 530.