Numbers 10:9-10

⁹If ye shall go out of your land to battle against the enemies that fight against you, ye shall cry with trumps sounding, and the bethinking of you shall be before your Lord God, that ye be delivered from the hands of your enemies.

¹⁰If any time ye shall have a feast, and holidays, and calends, that is, the first day of the month, ye shall sing in trumps upon the burnt sacrifices, and the peaceable sacrifices, that those or they be to you into remembering of your God; I am your Lord God.