Musnad Ahmad 32:290

Yazid narrated to us, Hammam—meaning Ibn Yahya—informed us, from Qatadah, from Anas: "Az-Zubayr ibn al-Awwam and Abd al-Rahman ibn Awf complained to the Messenger of Allah (peace and blessings of Allah be upon him) about lice, so he granted them a concession to wear silk. I saw each one of them wearing a shirt made of silk."