Sunan Abi Dawud 2515
سنن أبي داود#2515SahihNarrated Mu'adh ibn Jabal: The Prophet (ﷺ) said: Fighting is of two kinds: The one who seeks Allah's favour, obeys the leader, gives the property he values, treats his associates gently and avoids doing mischief, will have the reward for all the time whether he is asleep or awake; but the one who fights in a boasting spirit, for the sake of display and to gain a reputation, who disobeys the leader and does mischief in the earth will not return credit or without blame
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniHasan
Muhammad Muhyi Al-Din Abdul HamidHasan
Zubair Ali ZaiSahih
In-book reference: 15:39