Musannaf Ibn Abi Shayba 3:5160

Ishaq ibn Mansur narrated to us, Isra'il narrated to us, from Ibrahim ibn Muhajir, from Ibrahim, from al-Aswad, who said: Ka'b met me in Bayt al-Maqdis (Jerusalem) and said: "Where are you from?" I said: "From the Mosque of Kufa." He said: "That I should have come from where you came from is more beloved to me than that I should give in charity a thousand dinars, placing every dinar of them into the hand of a poor person." Then he swore that it (Jerusalem) is the center of the earth, like the bottom of a basin.