Amir bin Sa'd narrates from his father (Sayyiduna Sa'd bin Abi Waqqas, may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "I make sacred the area between the two lava plains of Madinah, so that its thorny trees are not to be cut nor its game killed." And he said: "Madinah is better for them, if only they knew. No one leaves it out of aversion except that Allah puts in it, in his place, someone better than him. And no one remains steadfast through its hardship and difficulty except that I will be a witness or an intercessor for him on the Day of Resurrection."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9961