Musannaf Ibn Abi Shaybah 39388 — Reports on the letters of the Prophet

Sa'id bin al-Musayyib said: The Messenger of Allah (peace and blessings be upon him) wrote to Kisra, Caesar and the Negus: To proceed: "Come to a word common between us and you (which is) that we worship none but Allah, associate nothing with Him, and do not take one another as lords besides Allah." Then if they turn away, say: "Bear witness that we are Muslims." Sa'id bin al-Musayyib said: Kisra tore up the letter and did not even look at it. The Prophet (peace and blessings be upon him) said: He himself has been torn apart, and his nation has been torn apart too. The Negus believed, and those who were with him believed as well, and he sent a pair of garments as a gift to the Messenger of Allah (peace and blessings be upon him). The Messenger of Allah (peace and blessings be upon him) said: As long as he leaves you alone, leave them alone too. Caesar read the letter of the Messenger of Allah (peace and blessings be upon him) and said: I have not heard of a letter with "In the name of Allah, the Most Gracious, the Most Merciful" since the letter of the Prophet Sulayman. Then he sent a messenger to Sayyiduna Abu Sufyan (may Allah be pleased with him) and Sayyiduna al-Mughirah bin Shu'bah (may Allah be pleased with him), who were present as traders in Caesar's land. Caesar asked them about some of the circumstances of the Messenger of Allah (peace and blessings be upon him), and he asked them: Who are the people who follow him? They replied: His followers are weak people and women. Then he asked: Tell me, have those who went to him turned back? They replied: No. Caesar said: This man is a prophet. He will surely gain mastery over the land beneath my feet. If I were with him, I would kiss his feet.