Judges 6:37-40

behold, I will put a fleece of wool on the threshing-floor; if there be dew on the fleece only, and it be dry upon all the ground, then shall I know that thou wilt save Israel by my hand, as thou hast spoken. And it was so; for he rose up early on the morrow, and pressed the fleece together, and wrung the dew out of the fleece, a bowlful of water. And Gideon said unto God, Let not thine anger be kindled against me, and I will speak but this once: let me make trial, I pray thee, but this once with the fleece; let it now be dry only upon the fleece, and upon all the ground let there be dew. And God did so that night: for it was dry upon the fleece only, and there was dew on all the ground.