Musnad Ahmad 27:191

Isma'il narrated to us, Ma'mar narrated to us, from Abdullah ibn Muslim, the brother of al-Zuhri, from Hamzah ibn Abdullah ibn Umar, from his father, who said: The Messenger of Allah, may Allah bless him and grant him peace, said: "Begging will continue to be with one of you until he meets Allah, Blessed and Exalted is He, while there is not a piece of flesh on his face."