Musnad Ahmad 27:662

Muhammad ibn Abdullah narrated to us, Sufyan narrated to us, from Abdullah ibn Dinar, from Ibn Umar, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, appointed for the people of Medina Dhu al-Hulayfah, for the people of Najd Qarn, and for the people of Sham al-Juhfah." And he said: "These three I memorized from the Messenger of Allah, peace and blessings of Allah be upon him, and I was told that the Messenger of Allah, peace and blessings of Allah be upon him, said: 'And for the people of Yemen, Yalamlam.'" It was said to him: "And Iraq?" He said: "There was no Iraq on that day."