This principle of faith

Because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed. (John 20:29)

 Why must we always see in order to believe? We have the Bible promise, “[God] shall give His angels charge over you, to keep you in all your ways.” (Psalm 91:11) Is it not enough to believe because God’s Word says so?
 Seeing is the reward of believing, not the other way around.
 Why does it have to be this way? Why does God sometimes hide things from us? Why do we need to take everything by faith? The answer lies in that last word—”faith.” It wouldn’t be faith if we could see.
 This principle of faith is something on which God places a great deal of importance. It’s also something that He gives us credit for, because it is a sign of our love and trust in Him, that we believe Him and His spiritual power and the principles He lays out for us in His Word. — Misty Kay [1]

 Our lives are full of supposes. Suppose this should happen, or suppose that should happen; what could we do; how could we bear it? But, if we are living in the high tower of the dwelling place of God, all these supposes will drop out of our lives. We shall be quiet from the fear of evil, for no threatenings of evil can penetrate into the high tower of God. —Hannah Whitall Smith (1832–1911)

[1] Activated The Reward of Faith