Sahih al-Bukhari Book 78, Hadith 79
Allah's Messenger (ﷺ) went out to inform the people about the (date of the Night of decree (Al-Qadr). There
happened a quarrel between two Muslim men. The Prophet (ﷺ) said, "I came out to inform you about the
Night of Al-Qadr, but as so-and-so and so-and-so quarrelled, so the news about it had been taken
away; and may be it was better for you. So look for it in the ninth, the seventh, or the fifth (of the last
ten days of Ramadan).
A man from the companions of the Prophet (ﷺ) said, "Two men abused each other in front of the Prophet (ﷺ) and one of them became angry and his anger became so intense that his face became swollen and changed. The Prophet (ﷺ) said, "I know a word the saying of which will cause him to relax if he does say it." Then a man went to him and informed him of the statement of the Prophet (ﷺ) and said, "Seek refuge with Allah from Satan." On that, angry man said, 'Do you find anything wrong with me? Am I insane? Go away!"
I saw Abu Dhar wearing a Burd (garment) and his slave too was wearing a Burd, so I said (to Abu Dhar), "If you take this (Burda of your slave) and wear it (along with yours), you will have a nice suit (costume) and you may give him another garment." Abu Dhar said, "There was a quarrel between me and another man whose mother was a non-Arab and I called her bad names. The man mentioned (complained about) me to the Prophet. The Prophet (ﷺ) said, "Did you abuse so-and-so?" I said, "Yes" He said, "Did you call his mother bad names?" I said, "Yes". He said, "You still have the traits of (the Pre-lslamic period of) ignorance." I said. "(Do I still have ignorance) even now in my old age?" He said, "Yes, they (slaves or servants) are your brothers, and Allah has put them under your command. So the one under whose hand Allah has put his brother, should feed him of what he eats, and give him dresses of what he wears, and should not ask him to do a thing beyond his capacity. And if at all he asks him to do a hard task, he should help him therein."