Musnad Ahmad 30:2542

Ibn Numayr narrated to us, he said: Hashim ibn Hashim narrated to us, he said: Abu Salih, the freed slave of the Sa‘diyyin, narrated to me, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, men will summon their clans, saying: 'The good, the good,' while Medina is better for them if they only knew. By the One in Whose hand is the soul of Muhammad, no one will endure its hardship and its severity, except that I will be a witness for him, or an intercessor, on the Day of Resurrection. By the One in Whose hand is the soul of Muhammad, it expels its inhabitants just as the bellows expels the dross of iron. By the One in Whose hand is the soul of Muhammad, no one will depart from it, desiring something else, except that Allah (Mighty and Majestic is He) will replace him with someone better than him."