سنن النسائي

It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) [SAW] said: 'Allah, the Mighty and Sublime, has guaranteed to the one who goes out in His cause, 'and he does not go out for any other purpose except Jihad in My cause and faith in Me, believing in My Messengers, but he is guaranteed that I will admit him to Paradise or I will send him back to his dwelling from which he set out, having acquired whatever he acquired of reward or spoils of war.'"