Riyad as-Salihin 1344 — The Book of Jihad

Abdullah bin 'Amr bin Al-'as Narrated from:

The Messenger of Allah (ﷺ) said, "A detachment of soldiers, large or small, who fights in the way of Allah, gets its share of booty and returns safe and sound, receives in advance two- thirds of its reward (only one-third remaining to its credit will be received in the Hereafter). And a troop of soldiers, large or small, that returns disappointed and is afflicted by misery, will receive its full reward (in the Hereafter)."[Muslim].