The letter to the King of Iran was sent through Abdullah bin Hudhafa(ra). The text of this letter was as follows:
In the name of Allah, the Gracious, the Merciful.. This letter is from Muhammad(sa), the Messenger of God, to Chosroes, the Chief of Iran. Whoever submits to a perfect guidance, and believes in Allah, and bears witness that Allah is One, and has no equal or partner, and that Muhammad(sa) is His Servant and Messenger, on him be peace. O King, under the command of God, I invite you to Islam. For I have been sent by God as His Messenger(sa) to all mankind, so that I may warn all living men and complete my Message for all unbelievers. Accept Islam and protect yourself from all afflictions. If you reject this invitation, then the sin of the denial of all your people will rest on your head (Zurqani and Khamis).
Abdullah bin Hudhafa(ra) says that when he reached the court of Chosroes he applied for admission to the royal presence. He handed over the letter to the Emperor and the Emperor ordered an interpreter to read it and explain its contents. On listening to the contents, the Chosroes was enraged. He took back the letter and tore it to pieces. Abdullah bin Hudhafa(ra) reported the incident to the Prophet(sa). On hearing the report, the Prophet(sa) said:
What the Chosroes has done to our letter even that will God do to his Empire (i.e., rend it to pieces).
The fit of temper which the Chosroes showed on this occasion was the result of the pernicious propaganda carried on against Islam by Jews who had migrated from Roman territory to Iran. These Jewish refugees took a leading part in anti-Roman intrigues sponsored in Iran, and had, therefore, become favourites at the Iranian court. The Chosroes was full of rage against the Prophet(sa). The reports about the Prophet(sa) which the Jews had taken to Iran, it seemed to him, were confirmed by this letter. He thought the Prophet(sa) was an aggressive adventurer with designs on Iran. Soon after, the Chosroes wrote to the Governor of Yemen, saying that one of the Quraish in Arabia had announced himself a Prophet(sa). His claims were becoming excessive. The Governor was asked to send two men charged with the duty of arresting this Quraishite and bringing him to the court of Iran. Badhan, the Governor of Yemen under the Chosroes, sent an army chief with a mounted companion to the Prophet(sa). He also gave them a letter addressed to the Prophet(sa), in which he said that on receipt of the letter the Prophet(sa) should at once accompany the two messengers to the court of Iran. The two planned to go first to Mecca. When somewhere near Ta’if, they were told that the Prophet(sa) lived in Medina. So they went to Medina. On arrival this army chief told the Prophet(sa) that Badhan, the Governor of Yemen, had been ordered by the Chosroes to arrange for the Prophet's(sa) arrest and despatch to Iran. If the Prophet(sa) refused to obey, he and his people were to be destroyed and their country made desolate. Out of compassion for the Prophet(sa), this delegate from Yemen insisted that the Prophet(sa) should obey and agree to be led to Iran. Having listened to this, the Prophet(sa) suggested that the delegates should see him again the following day. Overnight the Prophet(sa) prayed to God Who informed him that the insolence of the Chosroes had cost him his life. "We have set his own son against him, and this son will murder his father on Monday the l0th Jumad al-’Ula of this year." According to some reports, the revelation said, "The son has murdered the father this very night." It is possible that that very night was the l0th Jumad al-’Ula. In the morning, the Prophet(sa) sent for the Yemen delegates and told them of what had been revealed to him overnight. Then he prepared a letter for Badhan saying that the Chosroes was due to be murdered on a certain day of a certain month. When the Governor of Yemen received the letter he said, "If this man be a true Prophet(sa), it will be even as he says. If he be not true, then God help him and his country." Soon after, a boat from Iran anchored at the port of Yemen. It brought a letter from the Emperor of Iran to the Governor of Yemen. The letter bore a new seal, from which the Governor concluded that the prophecy of the Arabian Prophet(sa) had proved true. A new seal meant a new king. He opened the letter. It said:
From Chosroes Siroes to Badhan, the Governor of Yemen. I have murdered my father because his rule had become corrupt and unjust. He murdered the nobles and treated his subjects with cruelty. As soon as you receive this letter, collect all officers and ask them to affirm their loyalty to me. As for my father's orders for the arrest of an Arabian Prophet(sa), you should regard those orders as cancelled (Tabari, Vol. 3, pp. 1572–1574 and Hisham p. 46).
Badhan was so impressed by these events that he and many of his friends at once declared their faith in Islam and informed the Prophet(sa) accordingly.