Musnad Ahmad 5:593

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, from Hubayrah, from ‘Ali: "The Prophet, may Allah bless him and grant him peace, forbade me — or forbade — the *maytharah* (silk saddlecloth), the *qassi* (garment containing silk), and the gold ring."