Musannaf Ibn Abi Shayba 16:429

Abu Bakr narrated to us, he said: Abd al-Rahim ibn Sulayman narrated to us, from Muhammad ibn Ishaq, from Yazid ibn Abi Habib, from Abd al-Aziz ibn Abi al-Sa'ba, from Abu Aflah al-Hamdani, from Abdullah ibn Zurayr al-Ghafiqi, I heard him say: I heard Ali ibn Abi Talib say: The Messenger of Allah (may Allah bless him and grant him peace) took silk in his left hand and gold in his right hand, then he raised his hands with them and said: "Indeed, these two are forbidden for the males of my nation, and lawful for their females."