What is meant by the prohibition of two sales in one sale?

Question:
What is the meaning of the Prophet’s (peace and blessings be upon him) prohibition of two sales in one sale? And are the two sales in one sale the ones explained by the narrator of the hadith, Sulayman ibn Harb?

Answer:
Regarding the prohibited "two sales in one sale," scholars have differed in their interpretation. Some say it refers to a conditional sale, such as saying, "I will not sell you my house until you sell me your car or your house." This is a sale conditioned on another sale: "I will sell you this item on the condition that you sell me your specific item." This is two sales in one sale, and it is invalid. This is the first position of the Hanafis.
The second opinion is that "two sales in one sale" means selling an item for a deferred price and then buying it back from the seller for a lower, immediate price. This is known as the issue of 'inah.
This is the choice of Ibn al-Qayyim (may Allah have mercy on him). He held that "two sales in one sale" means selling an item for a deferred price and then buying it back from the seller for a lower, immediate price. This is the issue of 'inah, which is a stratagem to reach riba (usury or interest). It is as if he sold immediate dirhams for deferred dirhams that are more than the immediate amount, making the item merely a stratagem and a means to riba. The correct view is that "two sales in one sale" includes the first scenario and also this scenario; both fall under "two sales in one sale." Yes.