Musnad Abu Ya'la al-Mawsili 6:103

Musa ibn Hayyan narrated to us, Abd al-Malik ibn Amr Abu Amir al-Aqdi narrated to us, Khalid ibn Iyas al-Qurashi narrated to us, from Salih ibn Hassan, who said: I heard Sa'id ibn al-Musayyib saying: "Indeed, Allah is Good and loves goodness; He is Clean and loves cleanliness; He is Generous and loves generosity; He is Munificent and loves munificence. So clean your courtyards and your open spaces, and do not resemble the Jews who collect refuse in their houses." Khalid said: I mentioned that to Muhajir ibn Mismar, and he said: Amir ibn Sa'd narrated it to me, from his father, from the Prophet, peace and blessings of Allah be upon him, except that he said: "Clean your courtyards."