Musnad Abu Ya'la al-Mawsili 112:9

Suwayd ibn Sa'd narrated to us, Suwayd ibn 'Abd al-'Aziz narrated to us, from Nuh, from Ayyub, from al-Hasan, from Anas, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: Allah, Blessed and Exalted is He, says: "I am truly ashamed of My male servant and My female servant who grow old in Islam, such that the beard of My male servant and the hair of My female servant turn gray in Islam, that I should punish them in the Fire after that."