Collecting a debt from unlawfully earned wealth

Question

Question: Is it permissible or not for a Muslim creditor to collect his debt from a debtor — whether that debtor is a Muslim or poor (?) — when he knows that this wealth was earned in an impermissible way, or does not know? What is the ruling in both these cases?

Answer

If it is not known, collecting one’s debt is right. If it is known to be haram, then taking it from a non-Muslim is right, and from a Muslim it is makruh: [ar]ولو كان لمسلم على نصراني دين، فباع النصراني خمرًا وأخذ ثمنها وقضاه المسلم من دينه، جاز له أخذه؛ لأن بيعه له مباح.

Source: Fatawa Mahmudiyya

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