Musnad Abu Ya'la al-Mawsili 118:37

Harun ibn Ma'ruf narrated to us, Abdullah ibn Wahb narrated to us, Qurrah ibn Abd al-Rahman informed me that Ibn Shihab narrated to him, from Anas ibn Malik, who said: The Messenger of Allah (ﷺ) was sent as a prophet when he was forty years old. He remained in Makkah for ten years and in al-Madinah for ten years. He passed away when he was sixty years old, and there were not twenty white hairs on his head and his beard.