Musannaf Ibn Abi Shayba 16:444

Abu Bakr narrated to us, he said: Muhammad ibn Bishr narrated to us, he said: Sa'id narrated to us, from Qatadah, that Anas ibn Malik informed them that the Messenger of Allah (may Allah bless him and grant him peace) granted a concession to al-Zubayr ibn al-Awwam and to 'Abd al-Rahman ibn 'Awf for two silk shirts because of an ailment they had, which was itching.