Numbers 10:9

“Speak to the sons of Israel, saying, ‘In the seventh month on the first of the month you shall have a rest, a memorial by blowing of trumpets, a holy convocation.

And Moses sent them, one thousand from each tribe, to the war, and Phinehas the son of Eleazar the priest, to the war with them, and the holy vessels and the trumpets for the alarm in his hand.

“And behold, God is with us at our head and His priests with the signal trumpets to raise the shout of war against you. O sons of Israel, do not fight against Yahweh, the God of your fathers, for you will not succeed.”

My soul, my soul! I am in anguish! Oh, my heart! My heart is pounding in me; I cannot be silent Because you have heard, O my soul, The sound of the trumpet, The shout of war.

“Therefore behold, the days are coming,” declares Yahweh, “That I will cause a trumpet blast of war to be heard Against Rabbah of the sons of Ammon; And it will become a desolate heap, And her towns will be set on fire. Then Israel will take possession of his possessors,” Says Yahweh.

‘They have blown the trumpet and made everything ready, but no one is going to the battle, for My wrath is against all their multitude.

For if the trumpet produces an indistinct sound, who will prepare himself for battle?