Sahih Muslim Book 7, Hadith Number 3150.

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.

‘Abdullah b. Zaid b. ‘Asim (Allah be pleased with him) reported Allah’s Messenger (may peace be upon him) as saying: Verily Ibrahim declared Mecca sacred and supplicated (for blessings to be showered) upon its inhabitants, and I declare Medina to be sacred as Ibrahim had declared Mecca to be sacred. I have supplicated (Allah for His blessings to be showered) in its sa’ and its mudd (two standards of weight and measurement) twice as did Ibrahim for the inhabitants of Mecca. This Hadith has been narrated through another chain of transmitters with a slight variation of words.