We believe that Allah Almighty sent Muhammad (may Allah's peace and blessings be upon him) to all humankind. He, Glorified be He, says: {Say [O Prophet]: "O people, I am the Messenger of Allah to you all. To Him belongs the dominion of the heavens and earth; none has the right to be worshiped except Him; He gives life and causes death." So believe in Allah and His Messenger, the unlettered Prophet, who believes in Allah and His words, and follow him, so that you may be guided.} [Surat al-A‘rāf: 158] He Almighty also says: {We have not sent you [O Prophet] except as a bearer of glad tidings and a warner to all mankind, but most people do not know.} [Surat Saba’: 28]
And the Messenger of Allah (may Allah's peace and blessings be upon him) said: "I have been given five things which were not given to any prophet before me: I have been supported with horror for a distance of one month’s travel; the earth has been made for me a place for praying and a means for purification, so when the time of prayer comes, my followers can pray (wherever they may be); spoils of war have been made lawful for me; a prophet would be sent specifically to his people, and I have been sent to all humankind; and I have been granted the intercession." [Narrated by Al-Bukhāri (438), Muslim (521), and An-Nasā’i (432)]
Prophet Muhammad (may Allah’s peace and blessings be upon him) was sent to both worlds - humankind and jinn - by consensus among Muslims. Some jinn listened to the Qur'an and went back to their people as warners. Allah Almighty informed His Messenger about this in the Qur'an, saying: {And [remember] when We sent to you a group of jinn to listen to the Qur’an. When they heard it, they said [to one another]: "Listen attentively." Then when it was over, they returned to their people as warners. They said: "O our people, we have heard a scripture that has been sent down after Moses, confirming what came before it; it guides to the truth and to a straight path. O our people, respond to the one who is calling to Allah, and believe in him; He will forgive some of your sins and protect you from a painful punishment. And whoever does not respond to the one who is calling to Allah will have no escape on earth, nor will he have any protectors against Him; such people are clearly misguided."} [Surat al-Ahqāf: 29-32]
Allah, Exalted be He, took the covenant from all prophets and messengers (peace be upon them) that they would believe in Muhammad (may Allah’s peace and blessings be upon him) if he was sent as a messenger while they were alive. Allah Almighty says: {And [remember] when Allah took the covenant of the prophets, [saying]: "After I have given you the Book and wisdom, if there comes to you a messenger confirming what is with you, then you must believe in him and support him." Allah said: "Do you affirm this covenant and accept this commitment?" They said: "Yes, we do." He said: "Then bear witness and I am with you among the witnesses."} [Surat Āl ‘Imrān: 81] ‘Ali ibn Abi Tālib (may Allah be pleased with him) said: "Allah Almighty did not send any prophet - Adam and those who came after him - without taking the covenant from him regarding Muhammad: If he was sent while he was alive, he would believe in him and support him. And He would also command him to take the covenant from his people. He says: {And [remember] when Allah took the covenant of the prophets, [saying]: 'After I have given you the Book and wisdom...'} [Surat Āl ‘Imrān: 81]" [Narrated by At-Tabari in At-Tafsīr (5/540)]
And the Prophet (may Allah’s peace and blessings be upon him) said: "(I am) the supplication of Ibrāhīm, the glad tidings by ‘Īsa to his people, and the dream of my mother who saw that a light came out of her and illuminated the palaces of the Levant." [Narrated by Ahmad (17163), ‘Uthmān ibn Sa‘īd ad-Dārimi in Ar-Radd ‘Ala Al-Jahmiyyah (261), Ibn Abi ‘Āsim in As-Sunnah (418), ‘Abdullāh ibn Ahmad in As-Sunnah (865), Ibn Hibbān (6404), and At-Tabarāni in Musnad Ash-Shāmiyyīn (1455)] In another Hadīth, the Prophet (may Allah’s peace and blessings be upon him) said: "I am the supplication of my father Ibrāhīm." By this, he meant Prophet Ibrāhīm's supplication, which occurs in the verse that says: {Our Lord, send among them a messenger to recite to them Your revelations, teach them the Book and wisdom, and purify them. You are the All-Mighty, the All-Wise.} [Surat al-Baqarah: 129]
We believe that the prophets (peace be upon them) gave glad tidings to their people about the coming of Prophet Muhammad (may Allah’s peace and blessings be upon him), and that his traits and the traits of his Companions (may Allah be pleased with them) were mentioned in the Torah and the Gospel. Allah, the Exalted, says: {Muhammad is the Messenger of Allah, and those who are with him are firm against the disbelievers and compassionate among themselves. You see them bowing and prostrating [in prayer], seeking Allah’s grace and pleasure. Their distinguishing sign is on their faces from the effects of prostration. Such is their description in the Torah. And their description in the Gospel is like that of a seed that sprouts its shoot, then makes it strong; then it grows thick and stands straight on its stem, which delights the sowers – so that He may enrage thereby the disbelievers. Allah has promised those among them who believe and do righteous deeds forgiveness and a great reward.} [Surat al-Fat'h: 29] Allah Almighty also says: {Those who follow the Messenger – the unlettered Prophet – whose description they find in their Torah and the Gospel. He enjoins them to do what is good and forbids them from what is evil; he makes lawful for them what is pure and makes unlawful for them what is impure; he relieves them of their burden and the shackles that were on them. So those who believe in him, they honor and support him, and follow the light which is sent down with him – it is they who will be successful.”} [Surat al-A‘rāf: 157] Also, the Messiah (peace be upon him) informed the Children of Israel about his coming. He is quoted in the Qur'an as saying: {O Children of Israel, I am truly a messenger of Allah to you, confirming the Torah which came before me, and giving glad tidings of a messenger after me whose name will be Ahmad. But when he came to them with clear proofs, they said: "This is clear magic."} [Surat as-Saff: 6] The People of the Book recognized him as they recognized their children. Allah, Glorified be He, says: {Those whom We gave the Scripture recognize him [the Prophet] as they recognize their own sons, yet a group of them conceals the truth knowingly.} [Surat al-Baqarah: 146]
One of the signs of his prophethood, which were known among the People of the Book, was the Seal of Prophethood on the Prophet's shoulder. As-Sā’ib ibn Yazīd (may Allah be pleased with him) said: "Then, I stood behind him and looked at the Seal of Prophethood between his shoulders, like the button on a bride’s pavilion." [Narrated by Al-Bukhāri (190), Muslim (2345), and At-Tirmidhi (3643)]
Jābir ibn Samurah (may Allah be pleased with him) said: "And I saw the seal near his shoulder, the size of a pigeon's egg and its color was the same as that of his body." [Narrated by Muslim (2344), At-Tirmidhi (3644), and An-Nasā’i (5114)]
We believe in the universality of his message. That is why he sent letters to the kings and rulers inviting them to worship Allah Almighty alone and believe in his message. Abu Burdah related that his father (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) commanded us to proceed to the land of Negus. Mentioning the rest of the Hadīth, he said that Negus said: "I bear witness that he is the Messenger of Allah, and it is he about whom ‘Īsa (Jesus) the son of Mariyam gave good news. If it not were for the kingdom of which I am in charge, I would come to him and carry his shoes." [Narrated by Abu Dāwūd (3205), Ibn Aby Shaybah (37795), ‘Abd ibn Humayd (550), Ibn Abi ‘Āsim in Al-Āhad Wa Al-Mathāni (366), Ar-Ruwyāni (502), and Al-Hākim (3268)]
After receiving the Prophet's letter, Heraclius said: "I knew he would appear, but I did not think that he would be from amongst you. If what you say should be true, he will very soon occupy the earth under my feet, and if I knew that I would reach him definitely, I would go immediately to meet him; and if I were with him, I would wash his feet." [Narrated by Al-Bukhāri (2941) and Abu Dāwūd (5136)]
Hudhayfah reported: Al-‘Āqib and As-Sayyid, the rulers of Najrān, came to the Messenger of Allah (may Allah's peace and blessings be upon him) with the intention of doing li‘ān (taking an oath of condemnation) to him. One of them said to the other: "Do not do this, for, by Allah, if he was a prophet and we did this li‘ān, neither we nor our offspring after us would be successful." Then, both of them said: "We will give what you should ask for, but you should send a trustworthy man with us, and do not send any person with us but an honest one." The Prophet (may Allah's peace and blessings be upon him) said: "I will send an honest man who is really trustworthy." Thereupon, every one of the Prophet's Companions wished to be that one. Then, the Prophet (may Allah's peace and blessings be upon him) said: "Get up, O Abu ‘Ubaydah ibn al-Jarrāh." When he got up, the Messenger of Allah (may Allah's peace and blessings be upon him) said: "This is the trustworthy man of this Ummah." [Narrated by Al-Bukhāri (4380), Muslim (2420), At-Tirmidhi (3796), and Ibn Mājah (135)]
We believe that Allah Almighty drew the ends of the world together for the Prophet (may Allah's peace and blessings be upon him), and he saw the extent to which his Ummah's dominion would extend. The Prophet (may Allah's peace and blessings be upon him) said: "Indeed, Allah drew the ends of the world together for me, and I saw its eastern and western ends. The dominion of my Ummah will reach those ends which were drawn together for me." [Narrated by Muslim (2889), Abu Dāwūd (4252), At-Tirmidhi (2176), and Ibn Mājah (3952)]
One of the proofs for his prophethood is the conversion to Islam by many Jewish rabbis and Christian monks, and even by thousands and thousands among the People of the Book.
Moreover, the Prophet (may Allah's peace and blessings be upon him) fought the Romans and commanded His Companions to conduct Jihad against the Persians and the Romans after him.