Judges 6:36-40 (NASB)
Then Gideon said to God, "If You will deliver Israel through me, as You have spoken, 37behold, I will put a fleece of wool on the threshing floor. If there is dew on the fleece only, and it is dry on all the ground, then I will know that You will deliver Israel through me, as You have spoken." 38And it was so. When he arose early the next morning and squeezed the fleece, he drained the dew from the fleece, a bowl full of water. 39Then Gideon said to God, "Do not let Your anger burn against me that I may speak once more; please let me make a test once more with the fleece, let it now be dry only on the fleece, and let there be dew on all the ground." 40God did so that night; for it was dry only on the fleece, and dew was on all the ground.