A lender stipulates he can live rent-free in the borrower's courtyard until the loan is repaid. This is:
A courtyard produces steady rental income. The lender receiving free residence in exchange for the loan is Scriptural fixed interest — the benefit was clearly present at the time of the loan.
Question 2
A lender holds a mortgaged field and benefits from its produce without deducting anything. This is:
Field produce is not reliably present at the time of the loan — it may fail entirely. Therefore, profiting from it is only Rabbinic dust of interest.
Question 3
What makes a field mortgage fully permitted?
When the lender deducts a rental fee annually from the debt, the arrangement becomes a legitimate rental transaction rather than interest.
Question 4
Is it permitted to offer a lower annual rent if the tenant pays the whole year upfront?
Early payment discounts on rentals are explicitly permitted. The Rambam gives this as an example of permitted rental increase structures.
Question 5
Labor exchange — 'weed for me today and I'll weed for you tomorrow' — is permitted. What is forbidden?
Equal-for-equal exchanges of the same type of work are permitted. But swapping weeding for heavier hoeing, or summer plowing for harder rainy-season plowing, is forbidden as labor interest.