Sahih al-Bukhari Book 78, Hadith 78
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!"
(who was one of the companions who gave the pledge of allegiance to the Prophet (ﷺ) underneath the tree (Al-Hudaibiya)) Allah's Messenger (ﷺ) said, "Whoever swears by a religion other than Islam (i.e. if somebody swears by saying that he is a non-Muslim e.g., a Jew or a Christian, etc.) in case he is telling a lie, he is really so if his oath is false, and a person is not bound to fulfill a vow about a thing which he does not possess. And if somebody commits suicide with anything in this world, he will be tortured with that very thing on the Day of Resurrection; And if somebody curses a believer, then his sin will be as if he murdered him; And whoever accuses a believer of Kufr (disbelief), then it is as if he killed him."
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).