Gharar: forbidden uncertain sales

The uncertain sales

Gharar sales are those whose object or price is hidden or hazardous: ownership depends on chance, which produces gain and loss without a real exchange. The Sunnah names several, all invalid or prohibited.

• Mulamasa and munabadha: buying by a touch without examining, or by tossing the garment before looking at it. The Prophet forbade both (al-Bukhari 2144, Muslim 1512); no dispute is known on their invalidity (Ibn Qudamah): ownership suspended on chance is gambling and wrongful consumption.
• Intercepting the caravans: meeting incoming traders before the market to buy cheap: "let not the caravans be intercepted for sale" (al-Bukhari 2043, Muslim 1515). The sale is valid but sinful for the majority; a version of Ahmad and some Malikis void it, and the Prophet granted the trader an option on reaching the market.
• The townsman selling for the villager: "let no town dweller sell for a villager; leave people, Allah provides for some of them through others" (Muslim 1522), even if he is his brother or father (Muslim 1523): valid but forbidden for the majority, invalid for the Hanbali madhhab and some Malikis; the Hanafis rank it gravely disliked in scarcity.
• Muhaqala and muzabana: wheat on the ear against measured wheat, or fresh dates on the palm against measured dry dates. The Prophet forbade both (Muslim 3989); the scholars agree on their invalidity (Ibn al-Mundir), Ibn Abbas alone not reporting the prohibition; an-Nawawi ranks the muzabana as a riba of surplus by contract.
• Fruit before ripening: "do not buy fruits until they ripen" (al-Bukhari 2082, Muslim 1538), and the Prophet asked: if Allah withholds the fruit, how would one of you take his brother's wealth? (al-Bukhari 2086). The sale with a cutting condition is valid by agreement; with a remaining condition it is invalid for the majority, valid for Abu Hanifa, who orders the cutting.
• Food resold before possession: "whoever buys food must not resell it before taking full possession of it" (al-Bukhari 2025, Muslim 1526); the scholars agree on it (Ibn Abd al-Barr, al-Khattabi, Ibn Rushd), since reselling before possession is selling money against money with a surplus.
• The sale of years (mu'awama): selling the fruit of a palm for two or three years: void by consensus (an-Nawawi, Ibn al-Mundir), a sale of the nonexistent and the unknown.

Practical note

The common thread: everything that must be known (object, quality, quantity, possession) must be known before the contract. Advance orders exist, but in the disciplined form of salam.