Musnad Ahmad 435:82

Muhammad ibn Ja'far narrated to us, he said: Sa'id narrated to us, from Qatadah, from Abu Shaykh al-Huna'i, that he witnessed Mu'awiyah while there was a group of the Companions of the Prophet, may Allah bless him and grant him peace, with him. Mu'awiyah said to them: "Do you know that the Messenger of Allah, may Allah bless him and grant him peace, forbade riding on leopard skins?" They said: "Yes." He said: "Do you know that the Messenger of Allah, may Allah bless him and grant him peace, forbade wearing silk?" They said: "By Allah, yes." He said: "Do you know that the Messenger of Allah, may Allah bless him and grant him peace, forbade drinking from silver vessels?" They said: "By Allah, yes." He said: "Do you know that the Messenger of Allah, may Allah bless him and grant him peace, forbade wearing gold except if it is cut?" They said: "By Allah, yes." He said: "Do you know that the Messenger of Allah, may Allah bless him and grant him peace, forbade combining Hajj and 'Umrah?" They said: "By Allah, no." He said: "Then by Allah, it is indeed with them."