Judges 7:16-18

16And he divided the three hundred men into three 1units, and he put trumpets and empty pitchers into the hands of all of them, with torches inside the pitchers. 17Then he said to them, “Look at me and do likewise. And behold, when I come to the outskirts of the camp, 2do as I do. 18When I and all who are with me blow the trumpet, then you also blow the trumpets around the entire camp and say, ‘For the Lord and for Gideon!’”