The Messenger of Allah ﷺ said, "Among the major sins is that a man curses his own parents."They asked, "Messenger of Allah, would a man actually curse his own parents?"He replied, "Yes. He insults another man's father, and that man then curses his father in return, and he insults the other's mother, and that man curses his mother in return."
حدثنا قتيبة حدثنا الليث بن سعد عن ابن الهاد عن سعد بن إبراهيم عن حميد بن عبد الرحمن
قال رسول الله ﷺ من الكبائر أن يشتم الرجل والديه قالوا يا رسول الله وهل يشتم الرجل والديه قال نعم يسب أبا الرجل فيشتم أباه ويشتم أمه فيسب أمه
Agreed upon [by Bukhari and Muslim]. Muslim narrated it in the Book of Faith, chapter on major sins and the greatest of them, hadith no. 90, from Qutayba, and Bukhari narrated it, hadith no. 5973, from the hadith of Saad bin Ibrahim, with the same wording.