Abusing one's parents is one of the major sins. They (the hearers) said: Messenger of Allah, does a man abuse his parents too? He (the Holy Prophet) replied: Yes, one abuses the father of another man, who in turn abuses his father. One abuses his mother and he in turn abuses his (the former's) mother.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مِنَ الْكَبَائِرِ شَتْمُ الرَّجُلِ وَالِدَيْهِ قَالُوا يَا رَسُولَ اللَّهِ هَلْ يَشْتِمُ الرَّجُلُ وَالِدَيْهِ قَالَ نَعَمْ يَسُبُّ أَبَا الرَّجُلِ فَيَسُبُّ أَبَاهُ وَيَسُبُّ أُمَّهُ فَيَسُبُّ أُمَّهُ  

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  

"مِنَ الكَبَائِرِ شَتْمُ الرَّجُلِ وَالِدَيهِ، قيلَ: يَا رَسُولَ الله، وَهَلْ يَشْتِمُ الرَّجُلُ وَالِديه؟ . قَال: نَعَمْ، يَسُبُّ أَبَا الرَّجُلِ فَيَسُبُّ أَبَاهُ ويَسُبُّ أُمَّهُ، فَيَسُبُّ أُمَّهُ".