Sayyidina Umar ibn Khattab (RA) reported that he heard Allah’s Messenger (SAW) say, “There are four kinds of martyrs:
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(1) A believing man, strong in faith, meets the enemy, hoping for reward from Allah, till he is slain, for him, men will raise their eyes on the day of resurrection like this and he raised his head till his cap fell off. I do not know Umar’s (RA) cap or the Prophet (SAW)“ (2) A believing man of firm faith, meets the enemy but fearing him as though he is pricked by thorns. A sudden arrow strikes him and kills him. He is in the second category. (3) A believing man who has mingled (his) good deeds with evil deeds. He meets the enemy, hoping for reward from Allah till he is killed. This one is in the third category. (4) A believing man who has wronged his self (with sin), meets the enemy, hoping for reward from Allah till he is killed. This one is in the fourth category.” [Ahmed 146]