Messenger of Allah ﷺ sent his letter to Khusrau and ordered his messenger to hand it over to the Governor of Bahrain who was to hand it over to Khusrau. So, when Khusrau read the letter he tore it. Saʿid bin Al- Musaiyab said, "The Prophet ﷺ then invoked Allah to disperse them with full dispersion, (destroy them (i.e. Khusrau and his followers) severely)".
أَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ ﷺ بَعَثَ بِكِتَابِهِ إِلَى كِسْرَى فَأَمَرَهُ أَنْ يَدْفَعَهُ إِلَى عَظِيمِ الْبَحْرَيْنِ يَدْفَعُهُ عَظِيمُ الْبَحْرَيْنِ إِلَى كِسْرَى فَلَمَّا قَرَأَهُ كِسْرَى خَرَّقَهُ فَحَسِبْتُ أَنَّ سَعِيدَ بْنَ الْمُسَيَّبِ قَالَ فَدَعَا عَلَيْهِمُ النَّبِيُّ ﷺ أَنْ يُمَزَّقُوا كُلَّ مُمَزَّقٍ