—may Allah be pleased with him—was informed that one of his officials was accepting wine from non-Muslims under Muslim protection in payment of the jizya. He said, “May Allah curse so-and-so! Did he not know that the Messenger of Allah, may Allah bless him and grant him peace, said:

‘May Allah curse the Jews! Animal fat was forbidden to them, so they melted it down, sold it, and consumed its proceeds’?”

Then ʿUmar said, “Let them undertake its sale, and take the proceeds from them.” Thus, ʿUmar instructed them to accept from those non-Muslims the dirhams for which they had sold the wine, because they believed this to be permissible in their religion.

For this reason, the scholars said that if unbelievers conduct transactions among themselves which they believe to be permissible, receive the wealth exchanged, and subsequently embrace Islam, that wealth remains lawful for them. If they bring their case before us, we allow them to retain it, whether they seek our judgment before or after embracing Islam.

Allah Most High says:

“O you who believe, fear Allah and give up what remains due to you of usury, if you are believers.”

He commanded them to relinquish the usury still owed to them, but did not command them to return what they had already received, because they had regarded it as lawful.

If a Muslim conducts transactions which he believes to be permissible—such as the usurious legal devices that some followers of Abū Hanīfa permit in their fatwas—and receives the proceeds, or enters into a sharecropping agreement in which the cultivator supplies the seed, or leases land in return for a share of its yield, or undertakes similar transactions and receives the wealth, then other Muslims may, with even greater reason, transact with him concerning that wealth, even if they do not believe the original transaction to be permissible. Even if it later became clear to him that the stronger view was that it was forbidden, he would not be required to divest himself of the wealth he had earned