Numbers 10:1-5

1The Lord said to Moses: 2“Make two trumpets of hammered silver, and use them for calling the community together and for having the camps set out. 3When both are sounded, the whole community is to assemble before you at the entrance to the tent of meeting. 4If only one is sounded, the leaders—the heads of the clans of Israel—are to assemble before you. 5When a trumpet blast is sounded, the tribes camping on the east are to set out.