Musannaf Ibn Abi Shayba 33:125

Muhammad ibn Bishr narrated to us, he said: Isma'il narrated to us, from 'Amir, he said—and perhaps he said: Our companions narrated—from Abu Dharr, he said: My beloved (Khalil) advised me with seven things: To love the poor and to draw near to them. To look at those who are below me and not to look at those who are above me. To maintain ties of kinship even if they treat me harshly. To say "La hawla wa la quwwata illa billah" (There is no power and no strength except by Allah) frequently. To speak the bitter truth, not fearing the blame of any critic for the sake of Allah. And not to ask people for anything.