The final event that gave Gideon the courage to attack the Midianites was when he overheard a Midianite soldier’s dream about a loaf of barley bread tumbling into the Midianite camp and overturning a tent. Another soldier interpreted the dream, saying it symbolized Gideon’s victory over Midian.

This is recorded in Judges 7:13-15 (RSV):
"When Gideon came, behold, a man was telling a dream to his comrade, and he said, ‘Behold, I dreamed a dream; and lo, a cake of barley bread tumbled into the camp of Midian, and came to the tent, and struck it so that it fell, and turned it upside down, so that the tent lay flat.’"

Gideon was strengthened by this confirmation that God had given Midian into his hands.