Jabir b. ‘Abdallah told of a desert Arab who had sworn allegiance to God’s messenger, but who, when he suffered from a bout of fever in Medina, came to the Prophet and said, "Cancel my oath of allegiance, Muhammad;” but God’s messenger refused. He came again with the same request and again he refused. He came once more with the same request, and when he again refused, the desert Arab went off. God’s messenger then said, "Medina is like bellows which drives away its impurity and purifies what is good in it.”
Jabir b. Samura told that he heard God’s messenger say, “God called Medina Taba.”( Taj al-'Arus says the objection to the name Yathrib was owing to the fact that the root from which this name comes has the meaning of corruption. Therefore Taba, which comes from a root meaning to be good, sweet, or pure, was considered better. Other forms which have been used are Taiba, al-Mutayyaba (or al-Mutayyiba))
Abu Huraira reported God's messenger as saying, “The last hour will not come before Medina drives away its wicked people as the bellows drives away the impurity of iron."
Abu Huraira reported God’s messenger as saying, " I have been commanded to go to a town which will devour all towns. People call it Yathrib, but it is Medina. It drives away people as the bellows drives away the impurity of iron.”
