Sahih Muslim Book 7, Hadith Number 3181.

Chapter : Eminence of Medina, Allah’s Apostle (may peace be upon him) showered blessings upon it. Its sacredness and unlawfulness of hunting and lopping of trees and demarcation its precincts.

Yuhannis, the freed slave of Zubair, narrated that when he was sitting with Abdullah b. ‘Umar (Allah be pleased with him) during the days of turmoil, his freed slave-girl came to him. After saluting him she said: Abu Abd al-Rahmin, I have decided to leave (Medina) for the time is hard for us, whereupon Abdullah said to her: Stay here, foolish lady, for I have heard Allah’s Messenger (may peace be upon him) as saying: For one who shows endurance on the hardships and rigour of it (of Medina) I would be an intercessor or a witness on his behalf on the Day of Resurrection.