Shouting = Faith

I am not the writer of this inspiring piece, its from Streams in the Desert; the september 4th reading:

"Now, no on can suppose for a moment that this shout caused the walls [of jericho] to fall. And yet the secret of their victory lay in just this shout, for it was the shout of a faith which dared, on the authority of God's Word alone, to claim a promised victory, while as yet there were no signs of this victory being accomplished. And according to their faith God did unto them; so that, when they shouted, He made the walls to fall. "