Musnad Abu Ya'la al-Mawsili 3:247

'Abd al-Ghaffar ibn 'Abd Allah narrated to us, 'Ali ibn Mushir narrated to us, from Ash'ath, from Sa'id ibn Ashwa', from Hanash al-Kinani, from 'Ali ibn Abi Talib, that he called the chief of his police and said: "Go, and do not leave a grave without leveling it, and do not leave an ornamentation without removing it." Then he said: "Do you know for what I have sent you? I have sent you for that which the Messenger of Allah, may Allah bless him and grant him peace, sent me for."