Musnad Abu Ya'la al-Mawsili 6:11

Abu Khaythama narrated to us, Affan narrated to us, Abd al-Wahid ibn Ziyad narrated to us, Uthman ibn Hakim narrated to us, Amir ibn Sa’d informed me, from his father, who said: The Messenger of Allah (ﷺ) said: "Verily, I declare sacred what is between the two lava fields of Medina, just as Ibrahim declared his sanctuary sacred. Its thorny trees shall not be cut, its game shall not be hunted, and no one shall depart from it, desiring something else, but that Allah will replace him with someone better than him. And Medina is better for them, if they only knew. And no one shall intend evil for its people, but that Allah the Exalted will dissolve him, like the dissolving of lead in fire and the dissolving of salt in water."