Abu Shaykh al-Huna'i (may Allah have mercy on him) said: I heard Mu'awiyah (may Allah be pleased with him), while a group of the Companions of the Prophet (peace and blessings be upon him) were with him, say: I adjure you by Allah, do you know that the Messenger of Allah (peace and blessings be upon him) forbade wearing silk? They said: By Allah, yes.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16875