In March 628 CE, Muhammad had a dream. In it he was circumambulating the Ka'ba, walking the sacred rounds of Umrah at the shrine in Mecca, the city he had fled six years earlier. He decided to act on the dream. He invited his Bedouin allies in the outskirts of Medina to join him. Most declined, expecting no booty or anticipating hostilities with the Quraysh, Muhammad's own tribe and the ruling clan of Mecca. He set out anyway with about 1,500 Muslims, dressed as pilgrims, with sacrificial animals. Accounts disagree on whether they carried weapons, but the intent was clear: he was not approaching Mecca as an army. He was approaching as a pilgrim, knowing the Quraysh could not easily refuse a sacred pilgrimage without violating norms that predated Islam itself.

The Quraysh did not see it as pilgrimage. They sent a 200-strong cavalry to intercept. Muhammad took an unconventional route, avoided the cavalry, and pitched his tents at al-Hudaybiya, right on the border of the sacred territory surrounding the Ka'ba. Meccan emissaries came out to negotiate. The Quraysh declared that even if Muhammad had come in peace, they could not let him enter unconditionally, because the Bedouin would then say they had been forced. Muhammad sent Uthman into Mecca to negotiate. A rumor spread that Uthman had been killed. Muhammad gathered his followers under a tree and took their pledge to fight to the end, the oath that would be remembered as the Pledge of the Tree. Uthman turned out to be alive. The Quraysh sent Suhayl ibn Amr, one of their most capable negotiators, to settle the matter.

The treaty Suhayl and Muhammad agreed on had four main provisions. A ten-year truce between both parties. Any Qurayshi who fled to Muhammad without their guardian's permission would be returned, but any Muslim who went to the Quraysh would not be sent back, a one-sided clause that favored the Quraysh. Tribes could enter into covenant with whichever side they chose. The Muslims would return to Medina without performing pilgrimage this year, but would be allowed the following year and could stay in Mecca three days, carrying only sheathed swords, while the Quraysh vacated the city. After Ali wrote the treaty, Suhayl's own son Abu Jandal, already a convert to Islam, showed up trying to join Muhammad. The treaty had just been signed. Suhayl demanded his son back. Muhammad, bound by the terms he had just agreed to, returned Abu Jandal to his father. Umar and other Muslims were furious at what they saw as a surrender.

Muhammad called on his followers to shave their heads and sacrifice the animals they had brought. They hesitated. He set the example by shaving his own head and slaughtering his own animal. The rest followed. On the way back to Medina, Sura 48 of the Quran was revealed, declaring the treaty a clear victory. The historian Fred Donner has argued that securing a truce with the Meccans was the actual purpose of the whole pilgrimage attempt. Medina was hemmed in between hostile powers, the Jewish stronghold of Khaybar to the north and Mecca to the south, and genuinely vulnerable. Muhammad could not simply ask for a truce. By maneuvering to the edge of the sacred territory, dressed as pilgrims, he forced a situation in which the Quraysh had to negotiate. Donner calls it a desperate gamble. It could have ended in disaster had the Quraysh refused to make peace.

The truce held for a time, and that time changed everything. Tribes previously neutral were now free to align with either side. Muhammad won over several that had been linked to the Quraysh. He besieged and neutralized Khaybar to the north. Islam's appeal grew because the Quraysh had implicitly acknowledged Muhammad as their equal by treating with him, and because access to the Ka'ba for pilgrimage broadened the movement's reach. In 630, the Banu Bakr tribe, allied with the Quraysh, attacked the Banu Khuza'ah, allied with the Muslims. Muhammad demanded blood money or the treaty was void. When the Quraysh did not pay, he marched on Mecca with 10,000 men. The conquest was bloodless. He granted general amnesty, though ten individuals were initially excluded. Most of those were eventually forgiven too. Ibn Hisham, writing a century later, would sum up the shift: 'No previous victory in Islam was greater than this.'