In Muhammad's last years in Mecca, a delegation from Medina from its twelve important clans invited him as a neutral outsider to Medina to serve as the chief arbitrator for the entire community. There had been fighting in Medina involving mainly its pagan and Jewish inhabitants for around 100 years before 620. The recurring slaughters and disagreements over the resulting claims, especially after the Battle of Bu'ath in which all the clans had been involved, made it obvious to them that the tribal conceptions of blood feud and an eye for an eye were no longer workable unless there was one man with the authority to adjudicate in disputed cases. The delegation from Medina pledged themselves and their fellow citizens to accept Muhammad into their community and to protect him physically as if he was one of them.

After emigration to Medina, Muhammad drafted the constitution, “establishing a kind of alliance or federation” of the eight Medinan tribes and Muslim emigrants from Mecca and specifying the rights and duties of all citizens and the relationship of the different communities in Medina, including that of the Muslim community to other communities: the Jews and the other "Peoples of the Book".

One of the constitution's more interesting aspects was the inclusion of the Jewish tribes in the ummah because although the Jewish tribes were "one community with the believers", they also “have their religion and the Muslims have theirs.”

Another important feature of the Constitution of Medina is the redefinition of ties between Muslims. It sets faith relationships above blood-ties and emphasizes individual responsibility.

Tribal identities are still important to refer to different groups, but the “main binding tie” for the newly-created ummah is religion.

The Quran contains several verses regarding the origin of the Kaaba. It states that the Kaaba was the first House of Worship, and that it was built by Ibrahim and Ishmael on Allah’s instructions.

Ibn Kathir, the famous commentator on the Quran, mentions two interpretations among the Muslims on the origin of the Kaaba. One is that the shrine was a place of worship for Angels before the creation of man. Later, a house of worship was built on the location by Adam and Eve which was lost during the flood in Noah's time and was finally rebuilt by Abraham and Ishmael as mentioned later in the Quran. Ibn Kathir regarded this tradition as weak and preferred instead the narration by Ali ibn Abi Talib that although several other temples might have preceded the Kaaba, it was the first “House of God,” dedicated solely to Him, built by His instruction and sanctified and blessed by Him as stated in Quran 22:26-29. A Hadith in Sahih al-Bukhari states that the Kaaba was the First Mosque on Earth, and the Second Mosque was the Temple in Jerusalem.

While Abraham was building the Kaaba, an angel brought to him the Black Stone which he placed in the eastern corner of the structure. Another stone was the Maqam-e-Ibrahim (literally the Station of Abraham) where Abraham stood for elevation while building the structure. The Black Stone and the Maqam-e-Ibrahim are believed by Muslims to be the only remnant of the original structure made by Abraham as naturally the remaining structure had to be demolished and rebuilt several times over history for maintenance purposes. After the construction was complete, God enjoined the descendants of Ishmael to perform an annual pilgrimage: the Hajj and the Korban, sacrifice of cattle. The vicinity of the shrine was also made a sanctuary where bloodshed and war were forbidden.[Quran 22:26–33]

According to Islamic tradition, over the millennia after Ishmael's death, his progeny and the local tribes who settled around the oasis of Zam-Zam gradually turned to polytheism and idolatry. Several idols were placed within the Kaaba representing deities of different aspects of nature and different tribes. Several heretical rituals were adopted in the Pilgrimage (Hajj) including doing naked circumambulation.

In her book, Islam: A Short History, Karen Armstrong asserts that the Kaaba was officially dedicated to Hubal, a Nabatean deity, and contained 360 idols that probably represented the days of the year.

But by Muhammad's day, it seems that the Kaaba was venerated as the shrine of Allah, the High God. Once a year, tribes from all around the Arabian peninsula, whether Christian or pagan, would converge on Mecca to perform the Hajj, marking the widespread conviction that Allah was the same deity worshiped by monotheists. Guillaume in his translation of Ibn Ishaq, an early biographer of Muhammad, says the Kaaba itself was addressed using a feminine grammatical form.

Circumambulation was often performed naked by men and almost naked by women, and linked to ancient fertility rites. It is disputed whether Allah and Hubal were the same deity or different. Per a hypothesis by Uri Rubin and Christian Robin, Hubal was only venerated by Quraysh and the Kaaba was first dedicated to Allah, a supreme god of individuals belonging to different tribes, while the pantheon of the gods of Quraysh was installed in Kaaba after they conquered Mecca a century before Muhammad's time.

Prior to the spread of Islam throughout the Arabian Peninsula, the Kaaba was a holy site for the various Bedouin tribes of the area. Once every lunar year, the Bedouin tribes would make a pilgrimage to Mecca. Setting aside any tribal feuds, they would worship their pagan gods in the Kaaba and trade with each other in the city.

Various sculptures and paintings were held inside the Kaaba. A statue of Hubal, the principal idol of Mecca, and other pagan deities were in or around the Kaaba. There were paintings of idols decorating the walls. A picture of the Prophet ’Isa and his mother, Maryam, was situated inside the Kaaba and later found by the Prophet Muhammad after his conquest of Mecca. The iconography portrayed a seated Maryam with her child on her lap. This description, which would later become a universal iconography in later times, is similar to Christian art and its portrayal of the seated Virgin Mary holding a young Jesus in her lap. The iconography in the Kaaba also included paintings of other prophets and angels.

Throughout Muhammad's time (570-632 CE), the Kaaba was considered a holy and sacred site by the local Arabs. Muhammad took part in the reconstruction of the Kaaba after its structure was damaged due to floods around 600 CE. Ibn Ishaq's Sirat Rasūl Allāh, one of the biographies of Muhammad (as reconstructed and translated by Guillaume), describes Muhammad settling a quarrel between Meccan clans as to which clan should set the Black Stone cornerstone in place.

According to Ishaq's biography, Muhammad's solution was to have all the clan elders raise the cornerstone on a cloak, after which Muhammad set the stone into its final place with his own hands. Ibn Ishaq says that the timber for the reconstruction of the Kaaba came from a Greek ship that had been wrecked on the Red Sea coast at Shu'ayba and that the work was undertaken by a Coptic carpenter called Baqum. Muhammad's night journey is said to have taken him from the Kaaba to the Temple Mount and heavenwards from there.

Muslims initially considered Jerusalem as their qibla, or prayer direction, and faced toward it while offering prayers; however, pilgrimage to the Kaaba was considered a religious duty though its rites were not yet finalized.

In 624 CE, the direction of the qiblah was changed from Jerusalem to the Kaaba in Mecca.

At the culmination of his mission, in 630 CE, Muhammad conquered Mecca without violence from the Muslim army. His first action was to remove statues and images from the Kaaba. According to reports collected by Ibn Ishaq and al-Azraqi, Muhammad spared a painting of Mary and Jesus, and a fresco of Abraham; but according to Ibn Hisham, all pictures were erased.

Narrated Abdullah: When the Prophet entered Mecca on the day of the Conquest, there were 360 idols around the Ka’bah. The Prophet started striking them with a stick he had in his hand and was saying, “Truth has come and Falsehood has Vanished.” (Qur'an 17:81)

— Sahih Al-Bukhari, Book 59, Hadith 583

Muhammad ibn 'Abd Allah Al-Azraqi [9th-century Islamic commentator and historian] further conveys how Muhammad, after he entered the Kaaba on the day on the conquest, ordered all the pictures erased except that of Maryam.

“...Shihab (said) that the Prophet (peace be upon him) entered the Ka'ba the day of the conquest, and in it was a picture of the angels (mala'ika) and others, and he saw a picture of Ibrahim and he said: "May Allah kill those representing him as a venerable old man casting arrows in divination (shaykhan yastaqsim bi 'l-azlam)." Then he saw the picture of Maryam, so he put his hands on it and he said: “Erase what is in it [the Ka’ba] in the way of pictures except the picture of Maryam.”” — -al-Azraqi, Akhbar Mecca: History of Mecca

After the conquest Muhammad restated the sanctity and holiness of Mecca, including its Great Mosque, in Islam. He performed a lesser Pilgrimage (Umrah) in 629 CE, followed by the Greater Pilgrimage (Hajj) in 632 CE called the Farewell Pilgrimage since Muhammad prophesied his impending death on this event.

Hubal most prominently appeared at Mecca, where an image of him was worshipped at the Kaaba. According to Karen Armstrong, the sanctuary was dedicated to Hubal, who was worshipped as the greatest of the 360 idols the Kaaba contained, which probably represented the days of the year.

Hisham Ibn Al-Kalbi's Book of Idols describes the image as shaped like a human, with the right hand broken off and replaced with a golden hand. According to Ibn Al-Kalbi, the image was made of red agate, whereas Al-Azraqi, an early Islamic commentator, described it as of "cornelian pearl". Al-Azraqi also relates that it "had a vault for the sacrifice" and that the offering consisted of a hundred camels. Both authors speak of seven arrows, placed before the image, which were cast for divination, in cases of death, virginity, and marriage.

According to Ibn Al-Kalbi, the image was first set up by Khuzaymah ibn-Mudrikah ibn-al-Ya's' ibn-Mudar, but another tradition, recorded by Ibn Ishaq, holds that Amr ibn Luhayy, a leader of the Khuza'a tribe, put an image of Hubal into the Kaaba, where it was worshipped as one of the chief deities of the tribe. The date for Amr is disputed, with dates as late as the end of the fourth century AD suggested, but what is quite sure is that the Quraysh later became the protectors of the ancient holy place, supplanting the Khuza'a.

A tale recorded by Ibn Al-Kalbi has Muhammad’s grandfather Abdul Mutallib vowing to sacrifice one of his ten children. He consulted the arrows of Hubal to find out which child he should choose. The arrows pointed to his son Abd-Allah, the future father of Muhammad. However, he was saved when 100 camels were sacrificed in his place. According to Tabari, Abdul Mutallib later also brought the infant Muhammad himself before the image.

After defeat by Muhammad's forces at the Battle of Uhud, Abu Sufyan ibn Harb, leader of the Quraysh army, is said to have called on Hubal for support to gain victory in their next battle, saying "Show your superiority, Hubal". When Muhammad conquered Mecca in 630, he removed and had destroyed the statue of Hubal, along with the other 360 images at the Kaaba, and dedicated the structure to Allah.

There may be some foundation of truth in the story that Amr travelled in Syria and had brought back from there the cults of the goddesses ʻUzzāʼ and Manāt, and had combined it with that of Hubal, the idol of the Khuza'a. According to Al-Azraqi, the image was brought to Mecca "from the land of Hit in Mesopotamia" (Hīt in modern Iraq). Philip K. Hitti, who relates the name Hubal to an Aramaic word for spirit, suggests that the worship of Hubal was imported to Mecca from the north of Arabia, possibly from Moab or Mesopotamia.

Hubal may have been the combination of Hu, meaning "spirit" or "god", and the Moab god Baal meaning "master" or "lord". Outside South Arabia, Hubal's name appears just once, in a Nabataean inscription; there Hubal is mentioned along with the gods Dushara (ذو الشراة) and Manawatu — the latter, as Manat, was also popular in Mecca. On the basis of such slender evidence, it has been suggested that Hubal “may actually have been a Nabataean.” There are also inscriptions in which the word Hubal appears to be part of personal names, translatable as "Son of Hubal" or "made by Hubal".

Regional variants of the word Allah occur in both pagan and Christian pre-Islamic inscriptions. Different theories have been proposed regarding the role of Allah in pre-Islamic polytheistic cults. Some authors have suggested that polytheistic Arabs used the name as a reference to a creator god or a supreme deity of their pantheon. The term may have been vague in the Meccan religion. According to one hypothesis, which goes back to Julius Wellhausen, Allah (the supreme deity of the tribal federation around Quraysh) was a designation that consecrated the superiority of Hubal (the supreme deity of Quraysh) over the other gods. However, there is also evidence that Allah and Hubal were two distinct deities. According to that hypothesis, the Kaaba was first consecrated to a supreme deity named Allah and then hosted the pantheon of Quraysh after their conquest of Mecca, about a century before the time of Muhammad. Some inscriptions seem to indicate the use of Allah as a name of a polytheist deity centuries earlier, but we know nothing precise about this use. Some scholars have suggested that Allah may have represented a remote creator god who was gradually eclipsed by more particularized local deities. There is disagreement on whether Allah played a major role in the Meccan religious cult. No iconic representation of Allah is known to have existed. Allah is the only god in Mecca that did not have an idol. Muhammad's father's name was ʿAbd-Allāh meaning "the slave of Allāh".

Muslims believe the Quran to be the book of divine guidance revealed from God to Muhammad through the angel Gabriel over a period of 23 years and view the Quran as God's final revelation to humanity.

Revelation in Islamic and Quranic contexts means the act of God addressing an individual, conveying a message for a greater number of recipients. The process by which the divine message comes to the heart of a messenger of God is tanzil (to send down) or nuzūl (to come down). As the Quran says, "With the truth we (God) have sent it down and with the truth it has come down."

The Quran frequently asserts in its text that it is divinely ordained. Some verses in the Quran seem to imply that even those who do not speak Arabic would understand the Quran if it were recited to them. The Quran refers to a written pre-text, "the preserved tablet", that records God's speech even before it was sent down.

The issue of whether the Quran is eternal or created became a theological debate (Quran's createdness) in the ninth century. Mu’tazilas, an Islamic school of theology based on reason and rational thought, held that the Quran was created while the most widespread varieties of Muslim theologians considered the Quran to be co-eternal with God and therefore uncreated. Sufi philosophers view the question as artificial or wrongly framed.

Bernard Lewis believes that the advent of Islam was a revolution which only partially succeeded due to tensions between the new religion and very old societies that the Muslims conquered. He thinks that one such area of tension was a consequence of what he sees as the egalitarian nature of Islamic doctrine. Islam from the first denounced aristocratic privilege, rejected hierarchy, and adopted a formula of the career open to the talents. Lewis however notes that the equality in Islam was restricted to free adult male Muslims, but even that “represented a very considerable advance on the practice of both the Greco-Roman and the ancient Iranian world.”

Bernard Lewis writes about the significance of Muhammad's achievements:

The Constitution of Medina, also known as the Charter of Medina, was drafted by Muhammad in 622. It constituted a formal agreement between Muhammad and all of the significant tribes and families of Yathrib (later known as Medina), including Muslims, Jews, and pagans. The document was drawn up with the explicit concern of bringing to an end the bitter intertribal fighting between the clans of the Aws (Banu Aus) and Banu Khazraj within Medina. To this effect it instituted a number of rights and responsibilities for the Muslim, Jewish, and pagan communities of Medina bringing them within the fold of one community-the Ummah.

The precise dating of the Constitution of Medina remains debated but generally scholars agree it was written shortly after the hijra (622). It effectively established the first Islamic state. The Constitution established: the security of the community, religious freedoms, the role of Medina as a sacred place (barring all violence and weapons), the security of women, stable tribal relations within Medina, a tax system for supporting the community in time of conflict, parameters for exogenous political alliances, a system for granting protection of individuals, a judicial system for resolving disputes, and also regulated the paying of blood-wite (the payment between families or tribes for the slaying of an individual in lieu of lex talionis).

The Qur'an makes numerous references to slavery ([Quran 2:178], [Quran 16:75], [Quran 30:28]), regulating but thereby also implicitly accepting this already existing institution. Lewis states that Islam brought two major changes to ancient slavery which were to have far-reaching consequences. "One of these was the presumption of freedom; the other, the ban on the enslavement of free persons except in strictly defined circumstances," Lewis continues. The position of the Arabian slave was “enormously improved”: the Arabian slave "was now no longer merely a chattel but was also a human being with a certain religious and hence a social status and with certain quasi-legal rights.”

Lewis states that in Muslim lands slaves had a certain legal status and had obligations as well as rights to the slave owner, an improvement over slavery in the ancient world. Due to these reforms the practice of slavery in the Islamic empire represented a "vast improvement on that inherited from antiquity, from Rome, and from Byzantium."

To evaluate the effect of Islam on the status of women, many writers have discussed the status of women in pre-Islamic Arabia, and their findings have been mixed. Some writers have argued that women before Islam were more liberated, drawing most often on the first marriage of Muhammad and that of Muhammad's parents, but also on other points such as worship of female idols at Mecca. Other writers, on the contrary, have argued that women’s status in pre-Islamic Arabia was poor, citing practices of female infanticide, unlimited polygyny, patrilineal marriage and others.

Majid Khadduri writes that under the Arabian pre-Islamic law of status, women had virtually no rights, whereas Sharia (Islamic law) provided women with a number of rights. John Esposito states that the reforms affected marriage, divorce, and inheritance. According to Karen Armstrong, there were cultures, in the West and elsewhere, where women were not accorded the rights of inheritance and divorce until centuries later. The Oxford Dictionary of Islam states that the general improvement of the status of Arab women included prohibition of female infanticide, and recognizing women's full personhood.Gerhard Endress states: "The social system ... build up a new system of marriage, family and inheritance; this system treated women as an individual too and guaranteed social security to her as well as to her children. Legally controlled polygamy was an important advance on the various loosely defined arrangements which had previously been both possible and current; it was only by this provision (backed up by severe punishment for adultery), that the family, the core of any sedentary society could be placed on a firm footing."

But other scholars point out that there are records of women in pre-Islamic Mecca owning businesses, working as single women, and inheriting property, bringing into question the argument that Islam represented a clear advancement in the rights of women. Leila Ahmed argues that the independence and financial success of Muhammad’s first wife Khadijah, including “her economic independence, her initiating of her own marriage, and not even needing, apparently, a male guardian to act as intermediary (as was to be required by Islam), her marriage to a man many years younger than herself, and her remaining with him in a monogamous marriage (Mohamad had no other wife till after her death), all must reflect Jahilia, not Islamic, practice."

According to traditional Islamic beliefs, the Quran was revealed to Muhammad, starting one night during the month of Ramadan in 610 AD, when he, at the age of forty, received the first revelation from the angel Gabriel, who had given him the responsibility for inscribing these messages from God to give to mankind.

The Quran uses the term ummi to describe Muhammad. The majority of Muslim scholars interpret this word as a reference to an illiterate individual, though some modern scholars instead interpret it as a reference to those who belong to a community without a scripture.

Muslims believe that Gabriel brought the word of God to Muhammad verbatim, without any alteration or change. The Quran emphasizes that Muhammad was required only to receive the sacred text and that he had no authority to change it. It is also believed that God did not make himself known through the revelations; it was his will that was revealed. There is nothing in the Quran that suggests that Muhammad saw God during his revelations. For Muhammad, the revelations were real and he believed the context was objective, but he was only able to describe the experience through metaphorical terms.

After Muhammad would receive revelations, he would later recite it to his companions, who also memorized it or wrote it down. Before the Quran was commonly available in written form, speaking it from memory prevailed as the mode of teaching it to others. The practice of memorizing the whole Quran is still practiced among Muslims. Millions of people have memorized the entire Quran in Arabic. This fact, taken in the context of 7th-century Arabia, was not an extraordinary feat. People of that time had a penchant for recited poetry and had developed their skills in memorization to a remarkable degree. Events and competitions that featured the recitation of elaborate poetry were of great interest.

The society during the time of Muhammad was predominantly oral and for this reason he would recite the Quranic verses to his Companions for them to memorize. Therefore, it is unknown whether the Quran was ever written and collected during the time of Muhammad. While writing was not a common skill during Muhammad's time, Mecca, being a commercial center, had a number of people who could write. Some scholars believe that up to 48 scribes including Zayd ibn Thabit and Ubay ibn Ka'b recorded verses of the Quran. This provides an explanation as to how the Quran existed in written form during the life of Muhammad, even if it was not compiled into one text.

The word Ummah (pl. umam) means Nation in Arabic. For example the Arabic term for the United Nations in Arabic is الأمم المتحدة Al-Umam Al-Mutahedah, and the term الأمة العربية Al-Ummah Al-Arabeyah is used to refer to "The Arabic Nation".

The Word Ummah differs from the concept of a country or people. In it is greater context it is used to describe a larger group of people. For example, in Arabic the word شعب Sha’ab (“people”) would be used to describe the citizens of Turkey. However, the term Ummah is used to describe the Turkic Nation as a whole, which includes Turkey, Turkmenistan, Kazakhstan, Azerbaijan and other countries and ethnic groups in Central Asia.

The phrase Ummah Wāhidah in the Quran (أمة واحدة, “One Nation”) refers to all the Islamic world as it existed at the time. The Quran says: "You [Muslims] are the best nation brought out for Mankind, commanding what is righteous (معروف Ma'rūf, lit. "recognized [as good]") and forbidding what is wrong (منكر Munkar, lit. "recognized [as evil]")" [3:110].

The usage is further clarified by the Constitution of Medina, an early document said to have been negotiated by Muhammad in CE 622 with the leading clans of Medina, which explicitly refers to Jewish, Christians and pagan citizens of Medina as members of the Ummah.

At the time of Muhammad, before the conception of the ummah, Arab communities were typically governed by kinship. In other words, the political ideology of the Arabs centered around tribal affiliations and blood-relational ties.

In the midst of a tribal society, the religion of Islam emerged and along with it the concept of the ummah. The ummah emerged according to the idea that a messenger or prophet has been sent to a community. But unlike earlier messengers who had been sent to various communities in the past (as can be found among the Prophets in the Old Testament), Muhammad sought to develop a universal ummah and not only for the Arabs. Muhammad saw his purpose as the transmission of a divine message, and the leadership of the Islamic community. Islam sees Muhammad as the messenger to the ummah, transmitting a divine message, and implying that God is directing the life affairs of the ummah. Accordingly, the purpose of the ummah was to be based on religion, following the commands of God, rather than kinship.

Shura (Arabic: شورى‎ shūrā) is an Arabic word for “consultation.” The Quran and the Prophet Muhammad encourage Muslims to decide their affairs in consultation with those who will be affected by that decision.

Shura is mentioned as a praiseworthy activity often used in organizing the affairs of a mosque, Islamic organizations, and is a common term involved in naming parliaments.