Musnad Ahmad #144

Fadalah bin 'Ubaid said: I heard 'Umar bin al Khattab رضي الله عنه say: I heard the Messenger of Allah ﷺ say: ` The martyrs are four: a man who believes and has good faith, who meets the enemy and shows sincerity to Allah until he is killed - he is the one at whom people will look like this`- and he raised his head until the hat of the Messenger of Allah ﷺ or 'Umar's hat fell of. ` The second is a man who is a believer and has good faith, who meets the enemy and it is as if his back was beaten with the thorns of an acacia tree, then a stray arrow comes and kills him- he will be in a the second rank. The third is a man who is a believer, but he mixes good and bad deeds, and he meets the enemy and shows sincerity to Allah until he is killed- he will be in the third rank. The fourth is a believing man who transgresses against himself by committing a great deal of evil deeds and sins, who meets the enemy and shows sincerity to Allah until he is killed- he will be in the fourth rank.`