مُسْنَدُ أَحْمَدَ
Musnad Ahmad 4297
Musnad of Abdullah bin Mas'ood
It was narrated from 'Abdur-Rahman bin ' Abdullah bin Mas'ood from his father who said: The Messenger of Allah (ﷺ) cursed the one who consumes riba, the one who pays it, the two who witness it and the one who writes it down.
Musnad Ahmad 4327Its isnad is hasan]