Deuteronomy 20:1-4

When thou goest out to battle against thine enemies, and seest horses, and chariots, and a people more than thou, be not afraid of them: for the LORD thy God is with thee, which brought thee up out of the land of Egypt. And it shall be, when ye are come nigh unto the battle, that the priest shall approach and speak unto the people, and shall say unto them, Hear, O Israel, ye approach this day unto battle against your enemies: let not your hearts faint, fear not, and do not tremble, neither be ye terrified because of them; for the LORD your God is he that goeth with you, to fight for you against your enemies, to save you.