Among the sales in which these various kinds of gharar are found are two groups: transactions that are explicitly named in the sources, and transactions about which the sources keep silent. With the explicitly named sales, most are universally agreed upon, any dispute being confined to explaining what their names signify. As for the silent ones, the jurists differ over their ruling. We shall therefore begin with the forms expressly mentioned in the revealed Law and the legal discussion that attaches to them; afterwards we shall take up the silent forms whose disputed status is well known among the jurists of the various regions, so that the treatment may serve as a kind of rule within the discipline itself—that is, for referring secondary issues back to their principles.

The sales explicitly prohibited in the Law include:

• his—may God bless him and grant him peace—prohibition of ḥabl al-ḥabalah;
• his prohibition of selling what has not yet come into existence;
• of selling fruit before it begins to ripen;
• of the sales of mulāmasah and munābadhah;
• of the sale of ḥaṣāh;
• his prohibition of muʿāwamah;
• of “two sales in one sale”;
• of a sale combined with a stipulation;
• of combining a sale with a loan;
• of selling grain while the ear is still green and grapes before they turn black;
• and his prohibition of muḍāmīn and malāqīḥ.

As for bayʿ al-mulāmasah: in pre-Islamic times its form was that a man would merely touch a piece of cloth without unfolding it, or would purchase it at night. There is unanimous agreement that it is forbidden, and the ground of the prohibition is ignorance of the item’s qualities.

Bayʿ al-munābadhah was that each of the two parties would throw his garment to the other without specifying that this one was to be exchanged for that; they left the exchange to implicit mutual agreement.

Bayʿ al-ḥaṣāh took the form that the buyer would say, “Whichever garment the pebble I cast from my hand lands upon, the sale is concluded.” This is nothing but gambling.