Abdullah bin 'Amr narrated that :the Messenger of Allah said: "It is among the greatest of sins that a man should curse his parents." They said: "O Messenger of Allah! Does a man curse his parents?" He said: "Yes. He verbally abuses the father of a man, who in turn, verbally abuses his father, and he (retaliates and) curses his mother , so he curses his mother

English translation · Jami' at-Tirmidhi