Numbers 10:3-8

³And when they shall blow with them, the whole assembly shall gather to thee at the entrance of the tent of meeting.

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

⁵And when ye blow an alarm, the camps that lie eastward shall set forward.

⁶And when ye blow an alarm the second time, the camps that lie southward shall set forward; they shall blow an alarm on their setting forward.

⁷And when the congregation is to be gathered together, ye shall blow, but ye shall not blow an alarm:

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