Sayyiduna Salman al-Farisi (may Allah be pleased with him) said: We asked the Messenger of Allah (peace and blessings be upon him) what the ruling is on ghee, cheese and furs. He (peace and blessings be upon him) said: "The lawful is what Allah has made lawful in His Book, the unlawful is what Allah has made unlawful in His Book, and what He kept silent about is permissible."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19723