Sahih Muslim Book 20, Hadith Number 4690.

Chapter : The reward of one who fought and got his share of the booty and of one (who fought) but did not get any booty.

It has been narrated on the authority of ‘Abdullah b. ‘Amr that the Messenger of Allah (may peace be upon him) said: A troop of soldiers who fight in tile way of Allah and get their share of the booty receive in advance two-thirds of their reward in the Hereafter and only one-third will remain (to their credit). If they do not receive any booty, they will get their full reward.