Musannaf Ibn Abi Shayba 34:211

Affan narrated to us, Ali bin Mas'adah narrated to us, Ibrahim bin al-'Ala' al-Ghanawi narrated to us, he said: It reached us that Ka'b used to say: "Indeed, the first of the cities to be ruined are its two wings." We said: "And what are its two wings, O Ka'b?" He said: "Basra and Egypt."