Numbers 10:3-8

³And when they shall blow with them, all the congregation shall gather themselves unto thee at the door of the tent of meeting.

⁴And if they blow but with one, then the princes, the heads of the thousands of Israel, shall gather themselves unto thee.

⁵And when ye blow an alarm, the camps that lie on the east side shall take their journey.

⁶And when ye blow an alarm the second time, the camps that lie on the south side shall set forward; they shall blow an alarm for their journeys.

⁷But when the assembly is to be gathered together, ye shall blow, but ye shall not sound an alarm.

⁸And the sons of Aaron, the priests, shall blow with the trumpets; and they shall be to you for a statute for ever throughout your generations.