Numbers 10:2-8

2“Make two trumpets of hammered silver for calling the community to assemble and for signaling the breaking of camp.

3When both trumpets are blown, everyone must gather before you at the entrance of the Tabernacle.

4But if only one trumpet is blown, then only the leaders—the heads of the clans of Israel—must present themselves to you.

5“When you sound the signal to move on, the tribes camped on the east side of the Tabernacle must break camp and move forward.

6When you sound the signal a second time, the tribes camped on the south will follow. You must sound short blasts as the signal for moving on.

7But when you call the people to an assembly, blow the trumpets with a different signal.

8Only the priests, Aaron’s descendants, are allowed to blow the trumpets. This is a permanent law for you, to be observed from generation to generation.