Sahl bin Saad reported,

The Messenger of Allah ﷺ met the polytheists in battle and they fought one another. When the Messenger of Allah ﷺ withdrew to his camp and the others withdrew to theirs, there was among the companions of the Messenger of Allah ﷺ a man who would not leave any straggler from the enemy without pursuing him and striking him with his sword.The companions said, "No one of us has been as effective today as so-and-so."The Messenger of Allah ﷺ said, "He is among the people of the Fire."A man from the group said, "I will be his constant companion."So he went out with him. Whenever the man stopped, he stopped with him, and whenever he hurried, he hurried with him. Then the man received a severe wound and, seeking a swift death, he placed his sword on the ground with its tip between his breasts and pressed himself upon it, killing himself.The man returned to the Messenger of Allah ﷺ and said, "I bear witness that you are the Messenger of Allah."He asked, "What has happened?"He replied, "The man you mentioned earlier as being among the people of the Fire, the people found that hard to accept, so I said, 'I will track him for you.' I went out searching for him, and then he received a severe wound. Seeking a swift death, he placed the blade of his sword on the ground with its tip between his breasts and pressed himself upon it, killing himself."At that the Messenger of Allah ﷺ said, "A man may do the deeds of the people of Paradise, as it appears to people, while he is among the people of the Fire, and a man may do the deeds of the people of the Fire, as it appears to people, while he is among the people of Paradise."

عن سهل بن سعد الساعدي

أن رسول الله ﷺ التقى هو والمشركون فاقتتلوا، فلما مال رسول الله ﷺ إلى عسكره، ومال الآخرون إلى عسكرهم، وفي أصحاب رسول الله ﷺ رجل لا يدع لهم شاذة إلا اتبعها، يضربها بسيفه، فقالوا: ما أجزأ منا اليوم أحد كما أجزا فلان. فقال رسول الله ﷺ: أما إنه من أهل النار، فقال رجل من القوم: أنا صاحبه أبدا. قال: فخرج معه كلما وقف وقف معه، وإذا أسرع أسرع معه- قال:- فجرح الرجل جرحا شديدا، فاستعجل الموت، فوضع سيفه بالأرض وذبابه بين ثدييه، ثم تحامل على سيفه، فقتل نفسه، فخرج الرجل إلى رسول الله ﷺ فقال: أشهد أنك رسول الله قال: وما ذاك؟ قال: الرجل الذي ذكرت آنفا أنه من أهل النار، فأعظم الناس ذلك، فقلت: أنا لكم به. فخرجت في طلبه، ثم جرح جرحا شديدا، فاستعجل الموت، فوضع نصل سيفه في الأرض وذبابه بين ندييه، ثم تحامل عليه، فقتل نفسه. فقال رسول الله ﷺ عند ذلك إن الرجل ليعمل عمل أهل الجنة، فيما يبدو للناس، وهو من أهل النار، وإن الرجل ليعمل عمل أهل النار، فيما يبدو للناس، وهو من أهل الجنة.