Forced usury gains above the principal had to be given away as charity

Evidence

In the same way, if they force upon you the taking of usury, or some other unlawful thing, do it, but reject it in your heart, and only keep back for yourself the original capital sum invested, and if you repent, then give the rest away as charity. — L. P. Harvey, Muslims in Spain, 1500 to 1614, 327

Categorization

• QUESTION: The distinction between keeping the principal and giving the interest away is a practical, casuistic solution — but how enforceable or detectable was this ‘charity’ requirement in practice under Inquisition pressure?