Judges 7:16-19

16And he divided the three hundred men into three companies, and he put into the hands of all of them trumpets, and empty pitchers, with torches within the pitchers. 17And he said unto them, Look on me, and do likewise: and, behold, when I come to the outermost part of the camp, it shall be that, as I do, so shall ye do. 18When I blow the trumpet, I and all that are with me, then blow ye the trumpets also on every side of all the camp, and say, For Jehovah and for Gideon.

19So Gideon, and the hundred men that were with him, came unto the outermost part of the camp in the beginning of the middle watch, when they had but newly set the watch: and they blew the trumpets, and brake in pieces the pitchers that were in their hands.