Allah's Messenger (ﷺ) said, "I was ordered to migrate to a town which will swallow (conquer) other towns and is called Yathrib and that is Medina, and it turns out (bad) persons as a furnace removes the impurities of iron.
Sahih al-Bukhari Book 29, Hadith 5
← Previous Hadith We have nothing except the Book of Allah and this written paper from the Prophet (wherein is written:) Medina is a sanctuary from the 'Air Mountain to such and such a place, and whoever innovates in it an heresy or commits a sin, or gives shelter to such an innovator in it will incur the curse of Allah, the angels, and all the people, none of his compulsory or optional good deeds of worship will be accepted. And the asylum (of protection) granted by any Muslim is to be secured (respected) by all the other Muslims; and whoever betrays a Muslim in this respect incurs the curse of Allah, the angels, and all the people, and none of his compulsory or optional good deeds of worship will be accepted, and whoever (freed slave) befriends (take as masters) other than his manumitters without their permission incurs the curse of Allah, the angels, and all the people, and none of his compulsory or optional good deeds of worship will be accepted.

Sahih al-Bukhari Book 29, Hadith 4 Next Hadith → We came with the Prophet (ﷺ) from Tabuk, and when we reached near Medina, the Prophet (ﷺ) said, "This is Tabah."

Sahih al-Bukhari Book 29, Hadith 6