Musnad Abu Ya'la al-Mawsili 9:2

Muhammad ibn Abdullah ibn Numayr narrated to us, Muhammad ibn Bishr narrated to us, Ali ibn Salih narrated to us, from Abu Ishaq, from Abu Juhayfah, who said: They said, "O Messenger of Allah, may Allah bless him and grant him peace, you have turned gray." He said, "Hud and its sisters have turned me gray."