Sayyiduna Adi bin Hatim (may Allah be pleased with him) said: I came to the Prophet (peace and blessings be upon him) with a cross of gold around my neck. He (peace and blessings be upon him) said: "O Adi, throw this idol off your neck." So I threw it off. Then I reached him (peace and blessings be upon him) while he (peace and blessings be upon him) was reciting Surah Bara'ah, and he (peace and blessings be upon him) recited this verse: "They have taken their scholars and monks as lords besides Allah" [Surah al-Tawbah: 31], until he finished it. I said: "We do not worship them." He (peace and blessings be upon him) said: "Is it not the case that they make unlawful what Allah has made lawful, and you then regard it as unlawful; and they make lawful what Allah has made unlawful, and you then regard it as lawful?" I said: "Yes, indeed." He (peace and blessings be upon him) said: "That is their worship."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14290