Prohibition of Run Off From War

AL-ANFAL (SPOILS OF WAR, BOOTY) : 15-19

8:15. O ye who believe! when ye meet the Unbelievers in hostile array, never turn your backs to them.

8:16. If any do turn his back to them on such a day - unless it be in a stratagem of war, or to retreat to a troop (of his own)- he draws on himself the wrath of Allah, and his abode is Hell,- an evil refuge (indeed)!
8:17. It is not ye who slew them; it was Allah: when thou threwest (a handful of dust), it was not thy act, but Allah's: in order that He might test the Believers by a gracious trial from Himself: for Allah is He Who heareth and knoweth (all things).

8:18. That, and also because Allah is He Who makes feeble the plans and stratagem of the Unbelievers.
8:19. (O Unbelievers!) if ye prayed for victory and judgment, now hath the judgment come to you: if ye desist (from wrong), it will be best for you: if ye return (to the attack), so shall We. Not the least good will your forces be to you even if they were multiplied: for verily Allah is with those who believe!