Section
As for someone who conducts a sale involving usury without regarding usury as lawful, he is liable to a painful punishment unless excused on grounds of ignorance. The sale must be rescinded so long as it remains intact, according to Mālik and all his companions. The evidence for this is the report that “the Messenger of Allah ﷺ instructed the two Sa‘ds to sell gold or silver vessels from the spoils. They sold every three for four in coin, or every four for three in coin. The Messenger of Allah ﷺ said to them, ‘You have engaged in usury, so undo the transaction.’”
Section
If, however, the transaction can no longer be undone, he is entitled only to his principal, whether or not he has received the usurious gain. If he has received it, he must return it to its owner. Likewise, anyone who practises usury and then repents is entitled only to his principal. He must return whatever usurious gain he has received to the person from whom he received it. If he does not know who that person is, he must give it in charity on that person’s behalf, because Allah, Mighty and Majestic, says:
“But if you repent, you may have your principal.” [al-Baqarah: 279] The verse continues.
As for someone who embraces Islam and has usurious gains, whatever he has already received belongs to him, because Allah, Mighty and Majestic, says:
“So whoever receives an admonition from his Lord and desists may keep his past gains.” [al-Baqarah: 275]
And because the Messenger of Allah ﷺ said, “Whoever embraces Islam while possessing something may retain it.”
If, however, he has not yet received the usurious gain, it is unlawful for him to take it, and the person who owes it is released from that obligation. I know of no disagreement concerning this, because Allah, Mighty and Majestic, says:
“O you who believe, fear Allah and give up what remains of usury, if you are believers.” [al-Baqarah: 278]
This verse was revealed concerning people who embraced Islam while others owed them sums arising from usury they had charged them. They had collected some of it, while some remained outstanding,