What is the justification for profits on deferred payment for goods sold through an Islamic bank, and what is the Sharia-compliant method for distributing the collection of profits from the customer over the repayment period? Is the bank entitled to collect its profits from the installments paid by the customer on a decreasing and concentrated basis at the beginning of the repayment period without informing the customer, which leads to a difference in the final value of the good upon early settlement compared to what is sold to another customer for the same period?

Installment sales are permissible in principle, with their Sharia-compliant controls. Varying profits based on the repayment period is permissible, provided that a specific price is agreed upon at the time of the contract.

Waiving a portion of the deferred price in exchange for expediting its payment ("da' wa ta'ajjal" - waive and hasten) is prohibited by the majority of scholars. However, Ibn Abbas permitted it, and it is a narration from Ahmad, favored by Ibn Taymiyyah and Ibn al-Qayyim. The Islamic Fiqh Academy adopted this view, provided that it is not agreed upon at the time of the contract.

Based on the view of permissibility, there is no objection to the bank waiving any portion of the price it wishes, and it is not obligated to equalize the profit margin among customers with the same deferral period.