Numbers 10:4-6

New International Version - UK

⁴ If only one is sounded, the leaders – the heads of the clans of Israel – are to assemble before you. ⁵ When a trumpet blast is sounded, the tribes camping on the east are to set out. ⁶ At the sounding of a second blast, the camps on the south are to set out. The blast will be the signal for setting out.