that he cut the garment that has been sold and sew it, which is invalid because it combines two stipulations, and the ḥadith forbids “two stipulations in one sale.”

A better explanation than this and the other suggestions is the one that follows:
Ibn al-Qayyim said: The phrase “two stipulations in one sale” is explained by the seller’s statement, “Take this article for ten (dirhams) cash, and I will buy it back from you for twenty on deferred payment.”

This is precisely the transaction of ʿīnah, and it is the meaning that fits the ḥadith. If the real aim is to exchange ready money for a larger sum payable later, the seller is entitled only to the capital he advanced—the lower of the two prices. The wording allows no other sense; this is what is meant by “the two stipulations in one sale.”

If you wish the matter to become clear, reflect on his prohibitions of:
– two sales in a single sale,
– a loan together with a sale, and
– two stipulations in one sale;
all of these are avenues that lead to usury.

Third clause: “Nor profit on that for which no liability has been assumed.”
This has been given several explanations, but the soundest is that it refers to selling a specified commodity one has purchased before taking delivery and pocketing a profit on it. As noted earlier, the buyer may not resell an item until he has taken possession of it, because it remains under the seller’s liability should it perish. If he sells it before taking delivery, he earns a profit on property for which he carries no risk of loss, and that is impermissible. This is the purport of the Prophet’s saying, “Profit goes with liability” (Musnad Ahmad, 23091).

Fourth clause: “Nor sell what is not with you,” meaning what is not in your ownership or under your control. This is clarified by the ḥadith of Ḥakīm ibn Ḥizām, recorded by al-Nasāʾī (4534): “I said, ‘Messenger of Allah, a man comes to me wanting to buy something that I do not possess; may I then purchase it for him from the market?’ He replied, ‘Do not sell what you do not have.’”