“The believer does not slander, curse, or speak in an obscene or foul manner.” In a Hadeeth on the authority of Abu Hurayrah the Prophet
said:
“It does not befit a man of truth to be a curser.”
Al-Mughirah ibn Shu’bah reported: The Messenger of Allah, peace and blessings be upon him, said, “Do not abuse the dead and thus hurt the living.”
Source: Sunan al-Tirmidhī 1982
Grade:
Sahih (authentic) according to Al-Albani
Aisha reported: The Prophet, peace and blessings be upon him, said, “Do not abuse the dead, for they have reached what they put forward.”