From Sahih Muslim (Hadith 4925):
It has been narrated on the authority of 'Abdullah b. 'Amr that the Messenger of Allah (ﷺ) 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
Reference: Muslim 4925