Numbers 10:5-7 New King James Version (NKJV)

5. When you sound the advance, the camps that lie on the east side shall then begin their journey.

6. When you sound the advance the second time, then the camps that lie on the south side shall begin their journey; they shall sound the call for them to begin their journeys.

7. And when the assembly is to be gathered together, you shall blow, but not sound the advance.

Numbers 10