Musnad Ahmad 482:62

Yazid ibn Harun narrated to us, Muhammad ibn Ishaq narrated to us, from Yazid ibn Abi Habib; and al-Dahhak ibn Makhlad narrated to us, from Abd al-Hamid ibn Ja'far, [who said] Yazid ibn Abi Habib narrated to us, from Marthad ibn Abd Allah al-Yazani, from Uqbah ibn Amir al-Juhani, who said: A silk garment was gifted to the Messenger of Allah, may Allah bless him and grant him peace, so he wore it and prayed the Maghrib prayer with the people in it. When he finished his prayer, he pulled it off violently, then cast it aside. We said: "O Messenger of Allah, you wore it and prayed in it!" He said: "Indeed, this is not befitting for the God-fearing."