1 Corinthians 14:8
"For if the trumpet give an uncertain sound, who shall prepare himself to the battle?"
Cross References (ranked by relevance)
And if ye go to war in your land against the enemy that oppresseth you, then ye shall blow an alarm with the trumpets; and ye shall be remembered before the LORD your God, and ye shall be saved from your enemies.
My bowels, my bowels! I am pained at my very heart; my heart maketh a noise in me; I cannot hold my peace, because thou hast heard, O my soul, the sound of the trumpet, the alarm of war.
And it shall come to pass in that day, that the great trumpet shall be blown, and they shall come which were ready to perish in the land of Assyria, and the outcasts in the land of Egypt, and shall worship the LORD in the holy mount at Jerusalem.
Shall a trumpet be blown in the city, and the people not be afraid? shall there be evil in a city, and the LORD hath not done it?
Blow ye the trumpet in Zion, and sound an alarm in my holy mountain: let all the inhabitants of the land tremble: for the day of the LORD cometh, for it is nigh at hand;