Mālik’s guiding principle on this issue is that a lump-sum sale (jazāf) is permissible in anything sought for its bulk rather than for the individuality of its units. In his view such commodities fall into three categories:

1. Those whose normal manner of sale is by volume, yet which may still be sold by mere estimation; these are the items ordinarily measured or weighed.

2. Those whose normal manner is estimation, yet which may also be sold by measure; these are the items assessed by area, such as land and cloth.

3. Those for which measurement by volume or weight is impermissible altogether; they may only be sold by count and may not be sold on a lump-sum basis. These, as noted, are commodities desired for their discrete individual pieces.

Mālik also holds that gold dust and unminted silver may be sold without weighing, whereas minted dirhams and dinars may not. Abū Ḥanīfah and al-Shāfiʿī allow such sales but deem them disliked.

According to Mālik, it is likewise permissible to sell an unspecified heap on the basis of future measurement—meaning: “each measure of it for such-and-such a price.” Whatever number of measures the heap yields, after it has been measured and its quantity ascertained, is reckoned at that rate. Abū Ḥanīfah, however, obligates payment only for a single measure—the one explicitly named.

Mālik permits this form of contract with slaves, garments, and foodstuffs. Abū Ḥanīfah forbids it with garments and slaves, while—so far as I can tell—others prohibit it in all cases because the total price remains unknown.

Mālik further allows the purchaser to accept the seller’s own measurement so long as the sale is not on credit, for he suspects that the seller’s concession might amount to a gift meant to secure deferred payment. Other jurists do not permit reliance on the seller’s measurement until the buyer has measured the goods himself, invoking the Prophet’s prohibition—peace and blessings be upon him—against selling food “until the measuring scoops have passed over it.” Some scholars, however, permitted this outright. Among those who forbid reliance on the seller are Abū Ḥanīfah, al-Shāfiʿī, and Aḥmad; among those who allowed it unconditionally are ʿAṭāʾ ibn Abī Rabāḥ and Ibn Abī Mulaykah.

Mālik does not permit a seller who knows the measure to sell the measured commodity on a lump-sum basis to someone ignorant of that measure, and neither do al-Shāfiʿī and Abū Ḥanīfah.

The muzābanah transaction that the Prophet forbade, according to Mālik, falls under this heading: it is the sale of one unknown quantity for another. With commodities subject to usury the prohibition is due to the element of excess, whereas in other commodities it stems from the indeterminacy of the amount.

[Chapter Four: Conditional Sales and Thunyā]
[Sales Involving Conditions]

Chapter Four concerns sales that include stipulated conditions and the practice of thunyā. The defect in these contracts traces back to the gharar previously discussed, but because the revealed texts mention them expressly they have been given their own category among the invalid sales.

The basis of scholarly disagreement in this chapter rests on three ḥadīths. The first is the report of Jābir who said:

“The Messenger of God—peace and blessings be upon him—bought a camel from me and stipulated its mount until we reached Madinah.”

This ḥadīth is recorded in the Ṣaḥīḥ.