Is it permissible to sell a portion of divisible goods (Mutamathilat) previously acquired jointly and then divided, as a sale on Murabaha based on its share of the price?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
It is permissible to sell a portion of divisible goods, such as uniform wheat or barley, as a Murabaha sale based on its exact proportion of the total price. This view is held by Abu Thawr and the Ahl al-Ra'i, and no opposition is known regarding this matter. The permissibility stems from the certainty that the price for each unit or part is known precisely, similar to selling one 'qafiz' (measure) from an entire heap (ṣabra).
Supporting text
If a person enters into an Islam contract (advance payment contract) for two garments of the same description, takes possession of both according to the description, and wishes to sell one as Murabaha for half the price, the ruling is permissibility by analogy, as the price is equally divided based on the identical description in the liability (dhimmah), treating them as two equal measures from a heap. Any subsequent increase in quality in one garment after the sale is treated as an event occurring after the sale concluded.