Musnad Ahmad 937:227

Aswad ibn ‘Amir narrated to us, Isra’il narrated to us, from Ibrahim ibn Muhajir, from Mujahid, from Muwarriq, from Abu Dharr, who said: The Messenger of Allah said: "Verily, I see what you do not see, and I hear what you do not hear. The heaven has creaked, and it is right for it to creak. There is no space in it the size of four fingers except that there is an angel prostrating upon it. If you knew what I know, you would laugh little and weep much, and you would not take pleasure in women upon beds, and you would go out to the high grounds, crying out to Allah." Abu Dharr said: "By Allah, I wish that I were a tree that is cut down." *** Al-Hakam ibn Musa narrated to us, ‘Abd al-Rahman ibn Abi al-Rijal al-Madani narrated to us, ‘Umar, the freed slave of Ghafarah, informed us, from Ibn Ka‘b, from Abu Dharr, from the Prophet (peace and blessings of Allah be upon him), who said: "My Beloved commanded me with five things: to have mercy on the poor and sit with them; to look at those who are below me and not look at those who are above me; to maintain ties of kinship even if they turn away; to speak the truth even if it is bitter; and to say: 'There is no power and no strength except by Allah' (La hawla wa la quwwata illa billah)." The freed slave of Ghafarah says: "I do not know if anything remains among us of the five except this: our saying, 'There is no power and no strength except by Allah'." Abu ‘Abd al-Rahman said: I heard it myself from Al-Hakam ibn Musa, and he said: From Muhammad ibn Ka‘b, from Abu Dharr, from the Prophet (peace and blessings of Allah be upon him), the like of it.