The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 3154
Amir b. Sa'd reported on the authority of his father (Allah be pleased with him) that Allah's Messenger (may peace be upon him) said: I have declared sacred the territory between the two lava plains of Medina, so its trees should not be cut down, or its game killed; and he also said: Medina is best for them if they knew. No one leaves it through dislike of it without Allah putting in it someone better than he in place of him; and no one will stay there in spite of its hardships and distress without my being an intercessor or witness on behalf of him on the Day of Resurrection.