Musnad Ahmad 203:2

Muhammad ibn Ja‘far narrated to us, he said: Shu‘bah narrated to us, from Abu Ishaq, he said: I heard Abu al-Ahwas narrating from his father, he said: I came to the Messenger of Allah, peace and blessings of Allah be upon him, while I was in a disheveled state. He said: "Do you have wealth?" I said: "Yes." He said: "From what kind of wealth?" I said: "From all kinds of wealth: camels, slaves, horses, and sheep." He said: "If Allah has given you wealth, then let the effect of it be seen upon you." Then he said: "Do your people’s camels give birth to healthy-eared offspring, and you take a knife and cut their ears, and say: 'This is a *bahirah*,' and you slit them, or you slit their skins, and say: 'This is a *sarim*,' and you forbid them to yourself and your family?" I said: "Yes." He said: "For that which Allah, the Mighty and Majestic, has given you is yours. The arm of Allah is stronger, and the knife of Allah is sharper." (And sometimes he said: "The arm of Allah is stronger than your arm, and the knife of Allah is sharper than your knife.") He said: I said: "O Messenger of Allah, what do you think of a man who I stayed with, and he did not honor me, nor did he provide me hospitality, then he stayed with me; should I repay him for what he did, or should I provide him hospitality?" He said: "Provide him hospitality."