An Arabic term (وعد ملزم) that translates into binding promise; a wa’ad (promise) in which the promisor (al-wa’ed) is under legal and religious obligation to fulfill a specific act (effect) towards the promisee (al-maw’uood). In essence, this type of wa’ad actually amounts to a contract (aqd), and as a result, it should be subject to the typical conditions and stipulations of a valid contract such as:

1. Possession of the object of sale.
2. Immediate delivery of one of the countervalues or both.
3. Finality and definiteness of purchase or sale.

If the above conditions are not satisfied, a wa’ad might be tantamount to a manipulative ruse or trick (hilah) by which the impermissible (haram) would be rendered permissible (halal), particularly by selling what an individual doesn’t own (short selling) and the sale of debt for debt (ba’i al-kali bil kali). In this respect, the Maliki school of thought introduced a shari’a maxim maintaining that: “fundamentally, bilateral promising (i.e., muwa’adah) is impermissible for items which cannot be sold on spot”. For example, a promise (i.e., a unilateral promise) from one party to a currency exchange contract is permissible even if the promise is binding. However, a bilateral promise (muwa’adah) to purchase and sell currencies is forbidden by shari’a if the promise is binding, and regardless of the purpose of currency trading (e.g., hedging or risk management).

A wa’ad mulzim can also be attached to a murabahah contract (murabaha to the purchase orderer) where the orderer undertakes to accept the object of sale, when offered by the seller, by virtue of a juristically binding promise. With this promise, the orderer should accordingly proceed to enter into a formal contract of murabahah with the seller.