Musnad Ahmad 32:422

Abu Amir and Azhar ibn al-Qasim narrated to us, they said: Hisham narrated to us, from Qatadah, from Anas, that the Prophet, peace and blessings of Allah be upon him, said: "The likeness of what is between the two sides of my Basin is like what is between Medina and Sana'a, or like what is between Medina and Amman." And Azhar said: "The likeness." And he said: "And Amman."