Messenger of Allah ﷺ said. "It is one of the greatest sins that a man should curse his parents." It was asked (by the people), "O Messenger of Allah ﷺ! How does a man curse his parents?" The Prophet ﷺ said, "'The man abuses the father of another man and the latter abuses the father of the former and abuses his mother."  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّ مِنْ أَكْبَرِ الْكَبَائِرِ أَنْ يَلْعَنَ الرَّجُلُ وَالِدَيْهِ قِيلَ يَا رَسُولَ اللَّهِ وَكَيْفَ يَلْعَنُ الرَّجُلُ وَالِدَيْهِ قَالَ يَسُبُّ الرَّجُلُ أَبَا الرَّجُلِ فَيَسُبُّ أَبَاهُ وَيَسُبُّ أَمَّهُ