Mustadrak al-Hakim — Hadith 7551

Abu al-Ahwas narrates from his father (Sayyiduna Malik bin Nadlah (may Allah be pleased with him)): I came to the Prophet (peace and blessings be upon him) while I was in a shabby state. He (peace and blessings be upon him) asked: "Do you have wealth?" I said: "Yes." He (peace and blessings be upon him) asked: "What kind of wealth?" I said: "Every kind of wealth: camels, slaves, horses, and sheep and goats." He (peace and blessings be upon him) said: "Then since Allah has given you wealth, its effect should be seen on you." Then he (peace and blessings be upon him) said: "Are the camels of your people born with sound ears, and then you take a razor and cut off their ears and say, 'This is a bahirah,' and you slit their ears or their hides and say, 'These are surum,' and then you make them forbidden for yourself and your family?" He said: "Yes." He (peace and blessings be upon him) said: "Whatever Allah has given you is lawful for you. Allah's razor is sharper (meaning Allah's commands prevail over your self-invented customs)." Sometimes (the narrator) would say that he (peace and blessings be upon him) said: "Allah's strength is greater than your strength, and Allah's razor is sharper than your razor." I said: "O Messenger of Allah, what do you think: if I stay as a guest with a man and he does not host me, and then he comes to me as a guest, should I treat him as he treated me, or should I host him?" He (peace and blessings be upon him) said: "(No,) rather, host him."
This hadith is sahih al-isnad (its chain is authentic), but the two Shaykhs (Bukhari and Muslim) did not record it.