Musnad Abu Ya'la al-Mawsili 245:23

Muhammad ibn Yahya al-Basri narrated to us, Muhammad ibn Ya'qub narrated to us, he said: Ahmad ibn Ibrahim narrated to me, he said: Ishaq ibn Ibrahim ibn al-Ghamr, the freed slave of Samuk, narrated to me, he said: My father narrated to me, from my grandfather, he said: I heard Mu'awiyah ibn Hudayj saying: I was with Mu'awiyah ibn Abi Sufyan when a letter came to him from his governor informing him that he had encountered the Turks, defeated them, and that many of them were killed and much booty was taken. Mu'awiyah became angry at that, then he ordered that it be written to him: "I have understood what you mentioned regarding what you killed and what you took as booty. Do not let me know that you have returned to anything of that, nor that you have fought them until my command reaches you." I said to him: "Why, O Commander of the Faithful?" He said: "I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: 'The Turks will surely prevail over the Arabs until they reach their places of growth of the wormwood and the southernwood,' so I dislike fighting them for that reason."