Musannaf Ibn Abi Shayba 16:422

Abu Bakr narrated to us, he said: Muhammad bin Ubayd and Yazid bin Harun narrated to us, from Muhammad bin Ishaq, from Yazid bin Abi Habib, from Marthad bin Abdullah al-Yazani, from Uqbah bin Amir al-Juhani, who said: The Messenger of Allah (ﷺ) led us in the Maghrib prayer while he was wearing a *farruj*—meaning a *quba* (outer garment)—made of silk. When he finished his prayer, he pulled it off violently. I said: "O Messenger of Allah, you prayed while it was upon you?" He said: "Indeed, this is not appropriate for the God-fearing."