Musnad Ahmad 30:447

Abu Kamil narrated to us, Zuhayr narrated to us, Suhayl narrated to us, from his father, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Iraq has withheld its qafiz and its dirham, and al-Sham has withheld its mudd and its dinar, and Egypt has withheld its irdabb and its dinar. And you have returned to where you began, and you have returned to where you began, and you have returned to where you began." The flesh and blood of Abu Hurayrah bear witness to that. Abu Abd al-Rahman said: I heard Yahya ibn Ma'in mention Abu Kamil, and he said: "I used to take [hadith] from him regarding this matter, and Abu Kamil was a Baghdadi from the Abna'."