It is narrated from Salim bin Abdullah that I never heard my father, Sayyiduna Abdullah bin Umar (may Allah be pleased with them both), curse anyone except one man. And Salim used to say that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) informed that the Messenger of Allah (peace and blessings be upon him) said: "It is not befitting for a believer to be excessively cursing."

It is narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Indeed, Allah Almighty does not like one who is foul-mouthed, adopts foul language, and shouts in the markets."

It is narrated from Sayyidah Aisha (may Allah be pleased with her) that the Jews came to the Prophet (peace and blessings be upon him) and said: "Death be upon you." Sayyidah Aisha (may Allah be pleased with her) replied: "And death be upon you, and the curse of Allah and His wrath." The Prophet (peace and blessings be upon him) said: "O Aisha! Be gentle, and avoid harshness and foul speech." She said: "Did you not hear what they said?" The Prophet (peace and blessings be upon him) said: "Did you not hear what I replied to them? I returned their words upon them. Then my supplication against them is accepted, and theirs against me is not accepted."

It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), who reports from the Prophet (peace and blessings of Allah be upon him) that he said: "A believer is not one who curses excessively, is immoral, or uses obscene language."

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "A two-faced person is not worthy to be considered trustworthy."

Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: "The most despicable and base trait in the character of a believer is obscene speech."

It is narrated from Sayyiduna Ali bin Abi Talib (may Allah be pleased with him), he said: Those who curse excessively are themselves accursed. Marwan bin Mu'awiyah said: They are those who curse people.

It is narrated from Sayyiduna Abu Darda (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Those who frequently curse will neither be able to bear witness nor will they be entitled to intercede on the Day of Resurrection."

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "It is not befitting for a truthful person to curse frequently."

It is narrated from Sayyiduna Hudhaifah (may Allah be pleased with him), he said: When people curse each other, the curse definitely becomes binding upon them.