It happened the same night, that Yahweh said to him, Arise, get you down into the camp; for I have delivered it into your hand.
"This is nothing else save the sword of Gideon"  (Judges 7:14).  This revealed a very significant fact regarding the Midian host, namely, that they were fully aware of Gideon's identity, having no doubt heard of his exploits in destroying the altar of Baal.  Their intelligence service was also fully aware of the thousands who had rallied behind Gideon.