Its practical form is as follows: a man agrees to buy something and hands the seller a sum drawn from its price on the understanding that, should the sale be concluded, that sum will be counted toward the commodity’s price; but if the sale is not concluded, the buyer leaves that portion of the price with the seller and makes no claim to it. The majority of scholars forbid this arrangement because it involves gharar, undue risk, and the consumption of wealth without consideration.

Zayd used to say: “The Messenger of Allah—peace and blessings be upon him—permitted it.” The ḥadīth specialists reply that no sound report to this effect is known from the Messenger of Allah—peace and blessings be upon him.

[Sales Involving Thunyā]

Under the heading of exceptions (istithnāʾ) there are well-known questions over which the jurists have disagreed—namely, whether they fall under the Prophet’s prohibition of thunyā or not.

One such case is where a man sells a pregnant animal but excludes what is in its womb. The majority of the jurists of the various regions—Mālik, Abū Ḥanīfah, al-Shāfiʿī, and al-Thawrī—deem this impermissible, while Aḥmad, Abū Thawr, and Dāwūd allow it; it is also narrated from Ibn ʿUmar.

The point of contention is whether the excluded fetus is itself sold along with the mother, or whether, not being part of the sale, it remains the property of the seller. Whoever regards it as sold rules the transaction invalid and classifies it among the forbidden thunyā, owing to the ignorance of the fetus’s qualities and the uncertainty of its safe delivery. Whoever maintains that it remains the seller’s property permits the transaction.

Mālik’s position, in summary, is that when someone sells an animal and excludes a portion of it, that portion will be either (a) undivided, (b) specified, or (c) quantified.

(a) If it is an undivided share—such as selling a slave while excluding one quarter of him—there is no disagreement that the sale is valid.

(b) If it is a specified part, that part is either hidden, like a fetus, or visible. If hidden, the sale is invalid. If visible—such as the head, a hand, or a leg—then the animal is either of a kind whose slaughter is lawful or of one whose slaughter is not. If slaughter is not lawful, the sale is invalid, for one may not sell a slave and exclude his leg; his ownership rights are indivisible, and there is consensus on this. If slaughter is lawful and the seller, on the condition of slaughter, excludes a limb that has monetary value, the Mālikī school offers two opinions: the more famous view is that it is impermissible, while the other—attributed to Ibn Ḥabīb—permits it and specifically allows the sale of a sheep while reserving its legs and head.

(c) If the excluded part has no market value, there is unanimous agreement within the school that the transaction is valid. Mālik’s rationale is that, when the exclusion covers the skin, everything beneath the skin is concealed; and when the skin itself is not included, one cannot know in what state the limb will appear once the skin is removed. Ibn Ḥabīb counters that a specific, identifiable limb has been excluded, so the skin covering it is of no consequence; the precedent is buying grain in its husk or walnuts in their shell.

If, moreover, the excluded portion—whether by custom or by explicit stipulation—is a quantified part conditioned on slaughter, such as several pounds of camel meat, there are two reports from Mālik concerning its ruling.