Numbers 10:9
9 And pwhen 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.
Numbers 31:6
6 And Moses sent them to the war, a thousand from each tribe, together with Phinehas the son of Eleazar the priest, with the vessels of the sanctuary and the otrumpets for the alarm in his hand.
2 Chronicles 13:14
14 And when Judah looked, behold, the battle was in front of and behind them. And they cried to the Lord, and the priests blew the trumpets.