Language:
كتاب العلم
3  
Knowledge
(7)
Chapter: What is said regarding the hand to hand exchange (of books of knowledge), and the writing of knowledge by religious scholars to different countries
(7)
باب مَا يُذْكَرُ فِي الْمُنَاوَلَةِ وَكِتَابِ أَهْلِ الْعِلْمِ بِالْعِلْمِ إِلَى الْبُلْدَانِ
Sahih al-Bukhari 64

Narrated `Abdullah bin `Abbas:

Once Allah's Messenger (ﷺ) gave a letter to a person and ordered him to go and deliver it to the Governor of Bahrain. (He did so) and the Governor of Bahrain sent it to Chousroes, who read that letter and then tore it to pieces. (The sub-narrator (Ibn Shihab) thinks that Ibn Al-Musaiyab said that Allah's Messenger (ﷺ) invoked Allah against them (saying), "May Allah tear them into pieces, and disperse them all totally.)"

حَدَّثَنَا إِسْمَاعِيلُ بْنُ عَبْدِ اللَّهِ، قَالَ حَدَّثَنِي إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ صَالِحٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ بْنِ مَسْعُودٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عَبَّاسٍ، أَخْبَرَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم بَعَثَ بِكِتَابِهِ رَجُلاً، وَأَمَرَهُ أَنْ يَدْفَعَهُ إِلَى عَظِيمِ الْبَحْرَيْنِ، فَدَفَعَهُ عَظِيمُ الْبَحْرَيْنِ إِلَى كِسْرَى، فَلَمَّا قَرَأَهُ مَزَّقَهُ‏.‏ فَحَسِبْتُ أَنَّ ابْنَ الْمُسَيَّبِ قَالَ فَدَعَا عَلَيْهِمْ رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ يُمَزَّقُوا كُلَّ مُمَزَّقٍ‏.‏
Reference : Sahih al-Bukhari 64
In-book reference : Book 3, Hadith 6
USC-MSA web (English) reference : Vol. 1, Book 3, Hadith 64
  (deprecated numbering scheme)