It is narrated from Sayyiduna Abdullah bin Shaddad (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) wrote a letter to Heraclius, the king of Rome: "From Muhammad, the Messenger of Allah (peace and blessings be upon him), to Heraclius, the king of Rome. I invite you to Islam. If you accept Islam, you will have the rights and responsibilities of Muslims, and if you refuse, then leave the peasants so that they may become Muslims or pay jizya." When the letter reached Heraclius and he read it, his brother stood up and said: "Do not read this letter; he has put himself before you, he did not call you king, but rather the master of Rome." Heraclius said: "You are lying. If he began with his own name, then he is indeed the one who wrote to me, and if he called me the master of Rome, then I am truly the master of Rome; they have no ruler besides me." Then he began to read the letter, and out of intense fear, sweat began to flow from his forehead, even though it was the season of severe cold. He said: "Who knows this man?" So he summoned Abu Sufyan (may Allah be pleased with him). He asked: "Do you know this man?" Abu Sufyan said: "Yes." He asked: "How is his lineage among you?" He said: "He is of the highest lineage among us." He asked: "Where is his house in your village?" He said: "In the center of our village." So Heraclius said: "This is among the signs of his prophethood." Then he asked: "Do some of your people go to him and some come from him to you?" He said: "Our people go to him; they do not come to us." He asked: "Have you fought against him?" He said: "Yes." He asked: "Who prevailed?" He said: "He prevailed over us." He said: "This too is among the signs of his prophethood." Then Abu Sufyan said: "Do you not hear that he says he will prevail over all the earth?" Heraclius said: "If he is truly so, then he will surely prevail over the earth, even over whatever is beneath his feet. And if I were certain that he is the one, I would go to him myself and kiss his feet." Abu Sufyan says: "That was the first day I felt awe of Muhammad (peace and blessings be upon him)." He says: "This man was sitting on his throne, in his kingdom, in his fortresses, and just by reading the letter, sweat was pouring from his forehead. From that day I remained in fear of them until Allah guided me to Islam." And in that letter were these verses: «يَا أَهْلَ الْكِتَابِ تَعَالَوْا إِلَى كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ أَلَّا نَعْبُدَ إِلَّا اللَّهَ وَلَا نُشْرِكَ بِهِ شَيْئًا وَلَا يَتَّخِذَ بَعْضُنَا بَعْضًا أَرْبَابًا مِنْ دُونِ اللَّهِ فَإِنْ تَوَلَّوْا فَقُولُوا اشْهَدُوا بِأَنَّا مُسْلِمُونَ» and: «هُوَ الَّذِي أَرْسَلَ رَسُولَهُ بِالْهُدَى وَدِينِ الْحَقِّ لِيُظْهِرَهُ عَلَى الدِّينِ كُلِّهِ وَلَوْ كَرِهَ الْمُشْرِكُونَ» and: «قَاتِلُوا الَّذِينَ لَا يُؤْمِنُونَ بِاللَّهِ وَلَا بِالْيَوْمِ الْآخِرِ وَلَا يُحَرِّمُونَ مَا حَرَّمَ اللَّهُ وَرَسُولُهُ وَلَا يَدِينُونَ دِينَ الْحَقِّ مِنَ الَّذِينَ أُوتُوا الْكِتَابَ حَتَّى يُعْطُوا الْجِزْيَةَ عَنْ يَدٍ وَهُمْ صَاغِرُونَ» .

Then a bishop of Rome, Baghatir, who was the prayer leader of their kings, met some of the companions of the Messenger of Allah (peace and blessings be upon him) and said: "Write for me a surah from the Qur'an." So the companions wrote a surah for him. When he read it, he said: "This is indeed the Book of Allah which we recognize." Thus, he became Muslim but concealed his Islam. On Sunday, he did not go to his place of worship, nor did he go the next Sunday. When he was asked: "Are you ill?" the king summoned him and said: "You must come, or you will be brought by force." When he came, the king asked: "What is the matter?" He said: "This is the Book of Allah and the command of Allah, and this is the attribute of the Messiah that we know." The king said: "Alas, if I were to say this, the people of Rome would kill me." So Baghatir said: "But I say it." Then when he said this, the people seized him and tortured him severely, until his ribs were pulled out from his body, but he did not turn away from his religion until he was killed and burned.

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."

It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) sent us to Najashi. We were about eighty men, among whom were Sayyiduna Abdullah bin Mas'ud, Sayyiduna Ja'far bin Abi Talib, Sayyiduna Abdullah bin Arfatah, Sayyiduna Uthman bin Maz'un, and Sayyiduna Abu Musa Ash'ari (may Allah be pleased with them). We reached Najashi. The Quraysh sent Amr bin Al-As (may Allah be pleased with him) and Amarah bin Walid with gifts. When both of them reached Najashi, they prostrated before him and then stood on his right and left sides. Then they said: "Some people from our tribe have come to your land; they have abandoned our religion." Najashi asked: "Where are they?" They said: "They are in your land." So Najashi summoned them. Sayyiduna Ja'far (may Allah be pleased with him) said: "Today I will speak on your behalf." Thus, everyone followed him. Sayyiduna Ja'far greeted (with salam) but did not prostrate. The courtiers of Najashi said: "Why did you not prostrate to the king?" He replied: "We do not prostrate to anyone except Allah, the Mighty and Majestic." He was asked: "Why is that?" He said: "Allah Almighty has sent a Messenger among us and commanded us to prostrate only to Allah and to establish prayer and give zakat." Upon this, Amr bin Al-As said: "These people hold an opinion about Isa ibn Maryam and his mother that is contrary to yours." Najashi asked them: "What do you say about Isa and Maryam?" They said: "We say only what Allah Almighty has said: He is the Word of Allah and His Spirit, which He cast into Maryam, the virgin, the pure woman, whom no man touched, nor did she conceive from anyone." Hearing this, Najashi picked up a straw from the ground and said: "O people of Abyssinia, O priests and monks! By Allah, what these people say about Isa does not differ from us even as much as this straw." Then he said: "Welcome to you and to the One from whom you have come. I bear witness that he is the Messenger of Allah (peace and blessings be upon him), the very one whose mention we find in the Gospel, and the very one whose glad tidings were given by Sayyiduna Isa ibn Maryam. Live wherever you wish. By Allah, if it were not for the necessity of kingship, I would have gone myself to serve him, carried his sandals, and provided water for his ablution." Then he returned the gifts of Amr bin Al-As and Amarah bin Walid. Later, Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) returned home quickly and participated in Badr. And Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) narrated that when news of his (Najashi's) death reached the Messenger of Allah (peace and blessings be upon him), he prayed for his forgiveness.

Sayyiduna Sha'bi (may Allah have mercy on him) narrates that Ibn Baqilah, who was a resident of Hira, read out a letter to me. The size of the letter was equal to a palm. It was written in it: "In the name of Allah, the Most Gracious, the Most Merciful. From Khalid bin Walid (may Allah be pleased with him) to the chiefs of the people of Persia. Peace be upon him who follows guidance. To proceed! All praise is for Allah who has taken away your kingdom, weakened your strategies, scattered your group, and broken your service. So, accept protection from me and pay the jizya, and present such-and-such things as security. Otherwise, by Allah, besides whom there is no deity, I will attack you with such people who love death just as you love life."

Hazrat Mujahid (may Allah have mercy on him) says: "The polytheists will be fought until they accept Islam, and the People of the Book will be fought until they pay the jizya."