Musnad Ahmad 5:479

I read to Abd al-Rahman, from Malik, from Nafi’, and Ishaq—meaning Ibn ‘Isa—narrated to us, Malik informed me, from Nafi’, from Ibrahim ibn ‘Abd Allah ibn Hunayn, Ishaq said: from his father, from ‘Ali ibn Abi Talib: "That the Messenger of Allah (ﷺ) forbade the wearing of *al-qassi* (a type of silk-blend garment), and *al-mu’asfar* (garments dyed with safflower), and the wearing of gold rings, and the recitation of the Qur’an while bowing (*ruku’*)."