Judges 6:37
Behold, I will put a fleece of wool in the floor; and if the dew be on the fleece only, and it be dry upon all the earth beside, then shall I know that thou wilt save Israel by mine hand, as thou hast said. Behold, I will put a fleece of wool in the floor; and if the dew be on the fleece only, and it be dry upon all the earth beside, then shall I know that thou wilt save Israel by mine hand, as thou hast said.
The verse belongs to the time when Midian was oppressing Israel, and God raised up Gideon as a deliverer after the people turned back to him and confessed their sins. This deliverance fits the repeated pattern in which Israel's sins separated them from God, removed His strength from them, and brought them into subjection to nations they might have subdued. After backsliding and chastisement, followed by confession, God raised up a faithful and valiant man to put down idolatry and free them from their enemies.
In the verse Gideon, feeling his own insufficiency and acting cautiously because he needs confirmation before leading the army, asks for clear evidence that he is called and that God will be with him to save Israel by his hand. He proposes that dew fall on the fleece of wool alone while all the earth beside it remains dry. God grants the proposed sign so that the fleece is wet while the surrounding ground is dry. But Gideon remains uncertain because wool may naturally collect moisture and absorb it, so he wonders whether the result came from the nature of wool itself. He therefore asks for the sign to be renewed in reverse, and God grants that further request.
The verse is an example of setting a sign to determine God's will, but using such signs as a test for deciding duty is a delusion contrary to God's will. Confidence in these signs has led some believers to exchange wives and bring adultery into the church.