Numbers 10:1-5

Now the LORD said to Moses, “Make two trumpets of hammered silver for calling the community to assemble and for signaling the breaking of camp. When both trumpets are blown, everyone must gather before you at the entrance of the Tabernacle. But if only one trumpet is blown, then only the leaders—the heads of the clans of Israel—must present themselves to you. “When you sound the signal to move on, the tribes camped on the east side of the Tabernacle must break camp and move forward.