Sahih Bukhari Volume 4, Book 52, Hadith Number 190.
Narated By ‘Abdullah bin ‘Abbas : Allah’s Apostle 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. Said bin Al-Musaiyab said, “The Prophet then invoked Allah to disperse them with full dispersion, (destroy them (i.e. Khusrau and his followers) severely)”.