Musnad Abu Ya'la al-Mawsili 83:1

'Abd al-A'la ibn Hammad narrated to us, Hammad narrated to us, from 'Ali ibn Zayd, from Abu Hurrah al-Raqashi, from his uncle, who said: I was holding the rein of the she-camel of the Messenger of Allah (may Allah bless him and grant him peace) during the middle days of Tashriq in the Farewell Pilgrimage. He said, among the things he said: "O people, indeed every usury (riba) is abolished, and the first usury that is abolished is the usury of al-'Abbas ibn 'Abd al-Muttalib. You shall have your capital sums; you will not wrong, nor will you be wronged."