Judges 7:16-18

He divided the three hundred men into three companies. He gave each man a trumpet and an empty jar, with a torch in the jar. He said, “Watch me and do what I do. When I get to the edge of the camp, do exactly what I do. When I and those with me blow the trumpets, you also, all around the camp, blow your trumpets and shout, ‘For GOD and for Gideon!’”