"I heard the Messenger of Allah [SAW] say: 'A'udhu billahi minal-kufri wad-dain. (I seek refuge with Allah from Kufr and debt.)' A man said: 'O Messenger of Allah, are you equating debt with Kufr?' The Messenger of Allah [SAW] said: 'Yes.'" (Using translation from Nasāʾī 5473)
"أعوذُ باللهِ من الْكُفّرِ والدَّينِ، قِيلَ: أَتَعْدِلُ الدَّينَ بالكُفْر؟ قال: نعم".