Sunan Abi Dawud Book 15, Hadith 39
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.
‘Uqabah bin Amir Al Juhani said “I heard the Apostle of Allaah(ﷺ) recite when he was on the pulpit “Against them make ready your strength to the utmost of your power. Beware, strength is shooting, beware strength is shooting, beware strength is shooting.”
A man said: Messenger of Allah, a man wishes to take part in jihad in Allah's path desiring some worldly advantage? The Prophet (ﷺ) said: He will have not reward. The people thought it terrible, and they said to the man: Go back to the Messenger of Allah (ﷺ), for you might not have made him understand well. He, therefore, (went and again) asked: Messenger of Allah, a man wishes to take part in jihad in Allah's path desiring some worldly advantage? He replied: There is no reward for him. They again said to the man: Return to the Messenger of Allah. He, therefore, said to him third time. He replied: There is no reward for him.