" The messenger of Allah said: 'Shall I not tell you of the biggest of the major sins?' they said : 'Of course! O Messenger of Allah!' He said: 'To join partners with Allah, and disobeying one's parents.'"He said : " He sat up, and he had been reclining. He said: 'And false testimony, or false speech.' And the Messenger of Allah would not stop saying it until we said (to ourselves): 'I wish that he would stop.'"  

قَالَ رَسُولُ اللَّهِ ﷺ أَلاَ أُحَدِّثُكُمْ بِأَكْبَرِ الْكَبَائِرِ قَالُوا بَلَى يَا رَسُولَ اللَّهِ قَالَ الإِشْرَاكُ بِاللَّهِ وَعُقُوقُ الْوَالِدَيْنِ قَالَ وَجَلَسَ وَكَانَ مُتَّكِئًا فَقَالَ وَشَهَادَةُ الزُّورِ أَوْ قَوْلُ الزُّورِ فَمَا زَالَ رَسُولُ اللَّهِ ﷺ يَقُولُهَا حَتَّى قُلْنَا لَيْتَهُ سَكَتَ قَالَ وَفِي الْبَابِ عَنْ أَبِي سَعِيدٍ  

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."  

قَالَ رَسُولُ اللَّهِ ﷺ مِنَ الْكَبَائِرِ أَنْ يَشْتُمَ الرَّجُلُ وَالِدَيْهِ قَالُوا يَا رَسُولَ اللَّهِ وَهَلْ يَشْتُمُ الرَّجُلُ وَالِدَيْهِ قَالَ نَعَمْ يَسُبُّ أَبَا الرَّجُلِ فَيَشْتُمُ أَبَاهُ وَيَشْتُمُ أُمَّهُ فَيَسُبُّ أُمَّهُ