Musnad Abu Ya'la al-Mawsili 9:21

Zuhayr narrated to us, Hashim ibn al-Qasim and al-Hasan ibn Musa narrated to us, they said: Zuhayr narrated to us, from Abu Ishaq, from Abu Juhayfah, who said: I saw the Messenger of Allah, may Allah bless him and grant him peace, and there was some white [hair] on him, meaning his *‘anfaqah* (the hair between the lower lip and the chin). It was said to him: "What were you like on that day?" He said: "I was sharpening arrows and fletching them."