Hadith 4916
وَعَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مِنَ الْكَبَائِرِ شَتْمُ الرَّجُلِ وَالِدَيْهِ» . قَالُوا: يَا رَسُولَ اللَّهِ وَهَلْ يَشْتُمُ الرَّجُلُ وَالِدَيْهِ؟ قَالَ: «نَعَمْ يَسُبُّ أَبَا الرَّجُلِ فَيَسُبُّ أَبَاهُ ويسبُّ أمه فيسب أمه» . مُتَّفق عَلَيْهِ
Abdullah bin Amr (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: "A man's reviling his parents is a major sin." The Companions asked, "O Messenger of Allah! Does a man revile his own parents?" He (peace and blessings be upon him) replied: "Yes, he abuses another man's father, so (in return) that man abuses his father, and he abuses another man's mother, so (in return) that man abuses his mother." Agreed upon.