What is the ruling on purchasing land with a promise of receiving its value back as rent over a period of 7 years, or operating it for 20% of the production, and is it permissible to guarantee the rental due to fear of fraud in the production?

Scholars have differed on the permissibility of a contract within a contract, such as stipulating a lease within a sale. The majority of jurists prohibit this, considering it to be a form of "two sales in one sale" or "a sale with a forbidden condition." However, the Malikis and, in one narration, Ahmad, a view adopted by Ibn Taymiyyah and many contemporary scholars, permitted it. They interpreted the prohibition of "two sales in one sale" as referring to 'inah (buyback) sales. They permitted a condition as long as it was not a stratagem for usury or a loan that draws benefit.

Based on this preferred opinion, it is permissible to stipulate a lease within a sale, or to combine a sale with musaqah (sharecropping), such as buying land and the selling company undertaking its cultivation in exchange for a percentage of the produce. Jurists have detailed rulings regarding the obligations of the worker and the landowner in musaqah, and the preferred view is that it refers back to custom and what the two parties have agreed upon to prevent disputes.

In conclusion, the two scenarios mentioned (stipulating a lease within a sale and combining a sale with musaqah) are permissible.