Musnad Abu Ya'la al-Mawsili 3:224

Suwayd ibn Sa'id narrated to us, Harun ibn Muslim narrated to us, from al-Qasim ibn 'Abd al-Rahman, from Muhammad ibn 'Ali, from his father, from 'Ali, who said: The Messenger of Allah (may Allah bless him and grant him peace) said to me: "O 'Ali, perform the ablution thoroughly, even if it is difficult for you. Do not eat from the charity (sadaqah). Do not breed donkeys with horses. And do not sit with the astrologers."