Deuteronomy 20:2-4

ASV(i) 2 And it shall be, when ye draw nigh unto the battle, that the priest shall approach and speak unto the people, 3 and shall say unto them, Hear, O Israel, ye draw nigh this day unto battle against your enemies: let not your heart faint; fear not, nor tremble, neither be ye affrighted at them; 4 for Jehovah your God is he that goeth with you, to fight for you against your enemies, to save you.