Musnad Ahmad 26:777

'Affan narrated to us, Abu 'Awanah and Abu Nu'aym narrated to us, Isra'il narrated to us, from Simak, from 'Abd al-Rahman ibn 'Abd Allah ibn Mas'ud—'Affan said: Ibn 'Abd Allah ibn Mas'ud heard it from him—from his father, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) cursed the consumer of usury, the one who pays it, its two witnesses, and its scribe."