I heard `Umar bin `Abdul-Aziz asking As-Sa'ib, the nephew of An-Nimr. "What have you heard about residing in Mecca?" The other said, "I heard Al-Ala bin Al-Hadrami saying, Allah's Messenger (ﷺ) said: An Emigrant is allowed to stay in Mecca for three days after departing from Mina (i.e. after performing all the ceremonies of Hajj)"
Sahih al-Bukhari Book 63, Hadith 158
← Previous Hadith When Allah's Messenger (ﷺ) arrived at Medina, he alighted at the upper part of Medina among the people called Bani `Amr bin `Auf and he stayed with them for fourteen nights. Then he sent for the chiefs of Bani An-Najjar, and they came, carrying their swords. As if I am just now looking at Allah's Messenger (ﷺ) on his she-camel with Abu Bakr riding behind him (on the same camel) and the chiefs of Bani An- Najjar around him till he dismounted in the courtyard of Abu Aiyub's home. The Prophet (ﷺ) used to offer the prayer wherever the prayer was due, and he would pray even in sheepfolds. Then he ordered that the mosque be built. He sent for the chiefs of Banu An-Najjar, and when they came, he said, "O Banu An-Najjar! Suggest to me the price of this garden of yours." They replied "No! By Allah, we do not demand its price except from Allah." In that garden there were the (following) things that I will tell you: Graves of pagans, unleveled land with holes and pits etc., and date-palm trees. Allah's Messenger (ﷺ) ordered that the graves of the pagans be dug up and, the unleveled land be leveled and the date-palm trees be cut down. The trunks of the trees were arranged so as to form the wall facing the Qibla. The Stone pillars were built at the sides of its gate. The companions of the Prophet (ﷺ) were carrying the stones and reciting some lyrics, and Allah's Messenger (ﷺ) . . was with them and they were saying, "O Allah! There is no good Excel the good of the Hereafter, so bestow victory on the Ansar and the Emigrants. "

Sahih al-Bukhari Book 63, Hadith 157 Next Hadith → The Prophet's companions did not take as a starting date for the Muslim calendar, the day, the Prophet (ﷺ) had been sent as an Apostle or the day of his death, but the day of his arrival at Medina.

Sahih al-Bukhari Book 63, Hadith 159