Numbers 10:6-8

New King James Version

⁶ When you sound the advance the second time, then the camps that lie ^(A)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, ^(B)you shall blow, but not ^(C)sound the advance. ^8 (D)The sons of Aaron, the priests, shall blow the trumpets; and these shall be to you as an ^[a]ordinance forever throughout your generations.