The Messenger of Allah ﷺ said, "I have been commanded to go to a town that consumes other towns. People call it Yathrib, but it is Madinah. It expels people just as a blacksmith's bellows removes the impurities of iron."
حدثنا عبد الرحمن حدثنا مالك عن يحيى بن سعيد عن سعيد بن يسار
قال رسول الله ﷺ أمرت بقرية تأكل القرى يقولون يثرب وهي المدينة تنفي الناس كما ينفي الكير خبث الحديد
Its isnad is sahih. It is found in the Muwatta, p. 887, and Bukhari related it, 75:4-76, from Abdullah bin Yusuf, and Muslim, 1:389, from Qutayba bin Saeed, both of them from Malik, with the same wording.His saying, "I have been commanded regarding a town," means my Lord commanded me to migrate to it, or to settle in it. "It devours the towns" refers to the cities that will be conquered by its people, who will take spoils from them. "Eating" here is used metaphorically for conquest, because eating dominates what is eaten. Ibn Battal said, this is an instance of eloquent Arabic speech. The Arabs say, "We ate such-and-such land," meaning they prevailed over it."It expels the people" means it expels the wicked and the hypocrites.Al-kibr, with kasra on the kaf, Ibn Athir said, refers to the blacksmith's bellows, which is built of clay. It has also been said to mean the waterskin used to blow air onto the fire, and that the "built" structure is the furnace itself.