Musnad Ahmad 5:159

Khalaf ibn al-Walid narrated to us, Isra'il narrated to us, from Abu Ishaq, from al-Harith, from Ali, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, cursed the one who engages in usury, the one who consumes it, its two witnesses, the one who makes a woman lawful for her former husband (al-muhallil), and the one for whom she is made lawful (al-muhallal lahu)."