Numbers 10:9

And if ye go to war in your land against the enemy that oppresseth you, then ye shall blow an alarm with the trumpets, long-drawn blasts intended to call the people together and to inspire them with courage in shaking off the yoke of tyranny; and ye shall be remembered before the Lord, your God, and ye shall be saved from your enemies; the peals of the trumpets, assisted by the prayers of the faithful, would bring the people into the gracious remembrance of the Lord, who would help them against their oppressors.