Narrated Sahl bin Sa`d As Saidi:

Allah's Messenger (ﷺ) (and his army) encountered the pagans and the two armies.,, fought and then Allah's Apostle returned to his army camps and the others (i.e. the enemy) returned to their army camps. Amongst the companions of the Prophet (ﷺ) there was a man who could not help pursuing any single isolated pagan to strike him with his sword. Somebody said, "None has benefited the Muslims today more than so-and-so." On that Allah's Messenger (ﷺ) said, "He is from the people of the Hell-Fire certainly." A man amongst the people (i.e. Muslims) said, "I will accompany him (to know the fact)." So he went along with him, and whenever he stopped he stopped with him, and whenever he hastened, he hastened with him. The (brave) man then got wounded severely, and seeking to die at once, he planted his sword into the ground and put its point against his chest in between his breasts, and then threw himself on it and committed suicide. On that the person (who was accompanying the deceased all the time) came to Allah's Messenger (ﷺ) and said, "I testify that you are the Messenger of Allah." The Prophet (ﷺ) said, "Why is that (what makes you say so)?" He said "It is concerning the man whom you have already mentioned as one of the dwellers of the Hell-Fire. The people were surprised by your statement, and I said to them, "I will try to find out the truth about him for you." So I went out after him and he was then inflicted with a severe wound and because of that, he hurried to bring death upon himself by planting the handle of his sword into the ground and directing its tip towards his chest between his breasts, and then he threw himself over it and committed suicide." Allah's Messenger (ﷺ) then said, "A man may do what seem to the people as the deeds of the dwellers of Paradise but he is from the dwellers of the Hell-Fire and another may do what seem to the people as the deeds of the dwellers of the Hell- Fire, but he is from the dwellers of Paradise."