Numbers 10:1-9

And the LORD spake unto Moses, saying, Make thee two trumpets of silver; of a whole piece shalt thou make them: that thou mayest use them for the calling of the assembly, and for the journeying of the camps. And when they shall blow with them, all the assembly shall assemble themselves to thee at the door of the tabernacle of the congregation. And if they blow but with one trumpet, then the princes, which are heads of the thousands of Israel, shall gather themselves unto thee. When ye blow an alarm, then the camps that lie on the east parts shall go forward. When ye blow an alarm the second time, then the camps that lie on the south side shall take their journey: they shall blow an alarm for their journeys. But when the congregation is to be gathered together, ye shall blow, but ye shall not sound an alarm. And the sons of Aaron, the priests, shall blow with the trumpets; and they shall be to you for an ordinance for ever throughout your generations. And if ye go to war in your land against the enemy that oppresseth you, then ye shall blow an alarm with the trumpets; and ye shall be remembered before the LORD your God, and ye shall be saved from your enemies.