God fights our wars for us.

Deuteronomy 20:2 says, " And it shall be, when ye are come nigh unto the battle, that the priest shall approach and speak unto the people, 20:3 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; 20:4 For the LORD your God is he that goeth with you, to fight for you against your enemies, to save you." If god is going to fight for our soldiers then why do any of the Hebrews die in battle? Couldn't god just wipe them out for us? But what if the Hebrews fight other Hebrews? Who does he fight for. I have seen Christians fight other Christians. Who gets god on their side?