Numbers 10:2-5

2“Make yourself two trumpets of silver, you shall make them of hammered work; and you shall use them for 1summoning the congregation and breaking camp.

3Now 2when both are blown, all the congregation shall meet you at the entrance of the tent of meeting.

4But if only one is blown, then the 3leaders, the heads of the 4divisions of Israel, shall meet you.

5And when you blow an alarm, the camps that are pitched 5on the east side shall set out.