Abu Bakrah (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "Shall I not inform you of one of the gravest of the cardinal sins?" We said: "Yes, O Messenger of Allah!" He (ﷺ) said, "To join others as partners with Allah in worship and to be undutiful to one's parents." The Messenger of Allah (ﷺ) sat up from his reclining position (in order to stress the importance of what he was going to say) and added, "I warn you making a false statement and giving a false testimony. I warn you against making a false statement and giving a false testimony." The Messenger of Allah (ﷺ) kept on repeating this (warning) till we wished he should stop.

Abu Zaid Thabit bin Ad-Dahhak Al-Ansari (May Allah be pleased with him( (he is one of those who gave their pledge of allegiance to the Messenger of Allah (ﷺ) under the Tree) said: The Messenger of Allah (ﷺ) said, "He who swears by a religion other than that of Islam, is like what he has professed. He who kills himself with something, will be tormented with it on the Day of Resurrection. A person is not bound to fulfill a vow about something which he does not possess. Cursing a believer is like murdering him." .

Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said: "It does not befit a Siddiq (righteous Muslim) to frequently curse others."

Abud-Darda' (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "Those who frequently resort to cursing (people) would neither be accepted as witnesses nor as intercessors on the Day of Resurrection." .

Samurah bin Jundub (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "Do not curse one another, invoking Curse of Allah or Wrath of Allah or the fire of Hell." .

Ibn Mas'ud (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "A true believer is not involved in taunting, or frequently cursing (others) or in indecency or abusing." .

Abud-Darda' (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "When a person curses somebody or something, the curse goes up to heaven and the gates of heaven get closed. Then it comes down to the earth and its gates get closed. Then it turns right and left, and if it does not find an entrance to go anywhere, it returns to the person or thing that was cursed; if he or it deserves to be cursed; otherwise it returns to the person who uttered it." .

'Imran bin Husain (May Allah be pleased with him) said: We were with the Messenger of Allah (ﷺ) on a journey and there was a woman from the Ansar riding a she-camel. She abused and invoked curse upon it. The Messenger of Allah (ﷺ) heard it and said, "Off load the she- camel and set it free because it has been cursed." .

Abu Barzah Nadlah bin 'Ubaid Al-Aslami (May Allah be pleased with him) said: A young woman was riding a she-camel on which there was the luggage of people. Suddenly she saw the Prophet (ﷺ). The pass of the mountain became narrow for her people (because of fear). The young woman said to the she-camel: "Go ahead." When it did not move, she said, "O Allah! Curse it." The Prophet (ﷺ) said, "The she-camel that has been cursed should not accompany us." .

Ibn Mas'ud (May Allah be pleased with him) reported: The Messenger of Allah (ﷺ) said, "Reviling a Muslim is Fusuq (disobedience of Allah) and killing him is (tantamount to) disbelief." .

Abu Dharr (May Allah be pleased with him) reported: I heard the Messenger of Allah (ﷺ) saying, "When any Muslim accuses another Muslim of sin or of disbelief, the reproach rebounds upon the one who utters it, if the other person is not deserving of it." .

Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "When two persons indulge in abusing each other, the beginner will be the sinner so long as the oppressed does not transgress the limits." .

Abu Hurairah (May Allah be pleased with him) said: A drunkard was brought to the Prophet (ﷺ). He said, "Give him a beating." Then some beat him with their hands, some with their shoes, and some with (a folded) piece of cloth. When he left, someone said to him: "May Allah disgrace you!" The Prophet (ﷺ) said, "Do not help Satan overcome him by uttering such words." .

Abu Hurairah (May Allah be pleased with him) said: I heard the Messenger of Allah (ﷺ) saying, "He who accuses his slave of Zina will receive the punishment (Hadd) of slander on the Day of Resurrection, unless the accusation of Zina was true." .

'Aishah (May Allah be pleased with her) said: The Messenger of Allah (ﷺ) said, "Do not abuse the dead, because they have attained that which they had forwarded (i.e., their deeds, good or bad)." .

'Abdullah bin 'Amr bin Al-'As (May Allah be pleased with them) reported: The Messenger of Allah (ﷺ) said, "A (true) Muslim is one from whose tongue and hand the Muslims are safe; and a Muhajir (Emigrant) is he who leaves the deeds which Allah has prohibited." .

'Abdullah bin 'Amr bin Al-'As (May Allah be pleased with them) said: The Messenger of Allah (ﷺ) said, "He who desires to be rescued from the fire of Hell and to enter Jannah, should die in a state of complete belief in Allah and the Last Day, and should do unto others what he wishes to be done unto him." .

Anas bin Malik (May Allah be pleased with him) said: The Prophet (ﷺ) said, "Do not harbour grudge against one another, nor jealousy, nor enmity; and do not show your backs to one another; and become as fellow brothers and slaves of Allah. It is not lawful for a Muslim to avoid speaking with his brother beyond three days." .

Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (ﷺ) said, "The gates of Jannah are opened on Mondays and Thursdays, and then every slave (of Allah) is granted forgiveness if he does not associate anything with Allah in worship. But the person in whose heart there is rancour against his (Muslim) brother, they will not be pardoned and with regard to them it will be said twice: 'Hold both of them until they are reconciled with each other."' .

Abu Hurairah (May Allah be pleased with him) said: The Prophet (ﷺ) said, "Beware of envy because envy consumes (destroys) the virtues just as the fire consumes the firewood," or he said "grass." .