Numbers 10:6; Numbers 10:9

6 And when you blow an alarm the second time, the camps that are on the south side shall set out. An alarm is to be blown whenever they are to set out.

9 And when you go to war in your land against the adversary who oppresses you, then you shall sound an alarm with the trumpets, that you may be remembered before the LORD your God, and you shall be saved from your enemies.