Hazrat Sa'id bin al-Musayyib (may Allah have mercy on him) narrates that the Messenger of Allah (peace and blessings be upon him) wrote a letter to Caesar: "From Muhammad, the Messenger of Allah, to Caesar." In the letter, this verse was included: «تَعَالَوْا إِلَى كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ» [آل عمران: 64] meaning, "Come to a word that is equitable between us and you," up to the end of the verse: «مُسْلِمُونَ» [آل عمران: 64] meaning, "that we are Muslims." And the Prophet (peace and blessings be upon him) sent this same verse in letters to Khosrow and Negus as well. So when the letter reached Khosrow, he tore up Allah's letter and did not even look at it. The Messenger of Allah (peace and blessings be upon him) said: "Since he tore up Allah's letter, Allah will tear up his kingdom." But when Caesar read the letter of the Messenger of Allah (peace and blessings be upon him), he said: "This is the same kind of letter as I have seen for the first time since the Prophet Solomon." Then Caesar summoned Abu Sufyan (may Allah be pleased with him) and Mughirah bin Shu'bah (may Allah be pleased with him), and asked questions about the Messenger of Allah (peace and blessings be upon him). Both of them gave information about the Messenger of Allah (peace and blessings be upon him). Then Caesar said: "May my parents be sacrificed for him! Surely this man will rule even the lower parts of my land." Then the Messenger of Allah (peace and blessings be upon him) said: "Indeed, they too have a religion." And when Negus received the letter, he took the letter and called the Companions who were with him and said to them: "Go, and convey his message to your Prophet." The Messenger of Allah (peace and blessings be upon him) said about them: "Leave them as long as they leave you."