Musnad Abu Ya'la al-Mawsili 118:46

Abu Bakr ibn Zanjawayh narrated to us, Uthman ibn Salih narrated to us, Ibn Wahb narrated to us, from Yunus, from Ibn Shihab: Anas ibn Malik informed me that he heard the Prophet, may Allah bless him and grant him peace, saying while he was in Medina: "O Allah, place in it twice the amount of blessing that is in Mecca."