Numbers 10:4-7

“When a bugle gives a single, short blast, that’s the signal for the leaders, the heads of the clans, to assemble. When it gives a long blast, that’s the signal to march. At the first blast the tribes who were camped on the east set out. At the second blast the camps on the south set out. The long blasts are the signals to march. The bugle call that gathers the assembly is different from the signal to march.