Unilateral and Bilateral Promise

In Islamic Finance, many transactions begin long before a contract is actually concluded. Parties may need assurances that future transactions will take place, particularly when one side must incur costs, acquire assets, or make commercial preparations.

A unilateral promise (Wa‘d) occurs when one party undertakes to perform a future action for the benefit of another party. The recipient of the promise remains free to accept or decline the promised action when the time comes.

A bilateral promise (Muwa‘adah) consists of two corresponding promises exchanged between two parties regarding the same future transaction. Each party expresses an intention to perform a future act relating to the same subject matter.

The distinction is important because a promise is not itself a contract. A promise creates an expectation regarding future conduct, whereas a contract immediately creates enforceable rights and obligations through offer and acceptance.

Understanding this distinction helps explain many contemporary Islamic Finance structures, including Murabahah financing, Ijarah Muntahia Bittamleek, diminishing Musharakah, documentary credits, and supply agreements.

Commercial life often requires planning and commitment before a transaction can actually be completed.

A trader may need to purchase goods before finding a buyer. An Islamic bank may need to acquire an asset before selling it to a client. Importers and exporters may need assurances before arranging international shipments.

Without some form of undertaking, legitimate commercial activity could become difficult or excessively risky.

At the same time, Islamic law seeks to prevent promises from becoming tools for disguising prohibited transactions. A promise must not be used to recreate the economic effect of interest-bearing lending, nor should it become a mechanism for avoiding the genuine transfer of ownership, risk, and responsibility required by Shariah.

The framework therefore balances two objectives:

• Facilitating legitimate commercial certainty.
• Preventing promises from becoming vehicles for prohibited arrangements.

The central principle is that a promise is not a contract.

Even when a promise is legally enforceable, the future transaction does not come into existence automatically. The parties must still conclude the actual contract through a proper exchange of offer and acceptance at the relevant time.

This distinction preserves an important Shariah principle: contractual obligations should arise from a valid contract, not merely from an expression of future intention.

For example, when a client asks an Islamic bank to purchase an asset and promises to buy it afterward, the promise does not itself create a sale. The bank must first acquire ownership of the asset. Only afterward can a separate sale contract be concluded.

This separation ensures that ownership, risk, and liability genuinely pass through the stages required by Islamic commercial law rather than existing merely as legal formalities.

Promises Cannot Legitimize Prohibited Transactions

A promise cannot be used to circumvent Shariah prohibitions.

If a promise is designed to facilitate Riba-based outcomes, its form does not change its substance. A prohibited transaction remains prohibited even when it is structured through promises rather than contracts.

Similarly, promises that effectively create a repurchase arrangement resembling ‘Inah—where an asset is sold and then bought back in a manner that replicates a loan with interest—are impermissible.

The objective is clear: commercial forms must not be used to disguise lending for profit.

Moral Obligation and Legal Enforceability Are Different

Islam places great emphasis on fulfilling promises.

The Prophet ﷺ said:

The signs of a hypocrite are three: when he speaks, he lies; when he promises, he breaks his promise; and when he is entrusted, he betrays the trust.

As a result, fulfilling a promise is generally a religious obligation.

However, legal enforcement is a separate matter. Not every promise becomes legally binding. Legal enforceability arises when reliance on the promise causes another party to incur obligations, expenses, or commercial exposure.

This distinction protects both ethical accountability and commercial fairness.

Compensation Is Limited to Actual Loss

Where a binding promise is breached, compensation focuses on genuine harm.

The purpose is not to reward the disappointed party for hypothetical gains or expected profits. Rather, it is to restore losses actually suffered because of reliance on the promise.

Consequently, compensation is limited to actual loss and excludes opportunity cost or speculative profits that might have been earned elsewhere.

This reflects the Shariah preference for measurable justice rather than conjectural claims.

Binding Promises Remain One-Sided

A binding unilateral promise remains binding only on the promisor.

The beneficiary retains the option either to insist on performance or to waive the promise altogether.

This preserves the unilateral nature of the undertaking and prevents it from silently transforming into a bilateral contract.

Binding Bilateral Promises Are Exceptional

Normally, bilateral promises are morally binding but not legally enforceable.

However, commercial reality sometimes makes enforceability necessary. International trade conducted through documentary credits and certain supply arrangements may require legally binding bilateral promises because the underlying transaction cannot practically function otherwise.

Even then, the promised contract must still be concluded separately through offer and acceptance.

The promise creates enforceability regarding future commitment; it does not itself create the transaction.

A Promise Is Not the Same as a Contract

Many people assume that a binding promise automatically creates a sale, lease, or partnership.

It does not.

The promise may obligate a party to enter into a future contract, but the actual contract remains a separate legal event.

Binding Does Not Mean Immediate Transfer of Ownership

Ownership only transfers through the actual contract.

A promise cannot transfer title, create possession, or establish contractual rights that belong exclusively to a concluded transaction.

Bilateral Promise Is Not Necessarily a Forward Contract

A common misunderstanding is that two binding promises automatically create a future sale.

The Shariah distinction is important. Even when both parties are obligated to proceed, the final contract must still be concluded separately when the appropriate time arrives.

Master Agreements Do Not Create Transactions

Financial institutions frequently use master agreements that establish general procedures and terms for future dealings.

These agreements provide a framework but do not obligate either party to undertake a transaction. The actual transaction only arises when a separate offer and acceptance occur under that framework.

Murabahah Financing

A client asks an Islamic bank to purchase equipment and promises to buy it afterward.

The bank relies on this promise and acquires the equipment.

Because the bank has incurred a liability based on the client's undertaking, the promise becomes legally enforceable. However, the Murabahah sale itself is concluded only after the bank owns the equipment.

Ijarah Muntahia Bittamleek

An Islamic bank leases an asset and promises to transfer ownership to the lessee after all lease payments have been completed.

The transfer is based on a separate undertaking and occurs only when the agreed conditions have been fulfilled.

Diminishing Musharakah

An institution and a client jointly own an asset.

The institution may promise to lease its share, while the client may promise to purchase ownership units over time.

These promises facilitate the gradual transition of ownership while preserving the separate contractual nature of each stage.

Documentary Credits in International Trade

Importers and exporters often require enforceable commitments before goods are shipped.

In such situations, binding bilateral promises may be necessary because commercial practice and legal requirements make them indispensable to the transaction.

The framework reflects several foundational principles of Islamic commercial law.

First, transactions should be based on genuine consent and contractual clarity rather than ambiguity.

Second, ownership and risk should be real, not artificial. Commercial profit becomes legitimate when accompanied by exposure to ownership-related responsibilities.

Third, promises should promote trustworthiness. Islam encourages people to honor their commitments and discourages conduct that creates harm through broken expectations.

Fourth, Shariah rejects contractual structures that merely imitate interest-bearing lending through legal devices. The economic substance of a transaction matters alongside its legal form.

The permissibility of certain binding bilateral promises in modern trade demonstrates another important principle: Islamic law accommodates genuine commercial needs while preserving its ethical foundations.

• A promise is not a contract and does not automatically create a transaction.
• A unilateral promise binds only the promisor, not the beneficiary.
• Moral obligation and legal enforceability are distinct concepts.
• Legal enforceability arises primarily when reliance on a promise causes actual liability or loss.
• Compensation for breach is limited to actual loss and excludes opportunity cost.
• Promises cannot be used to disguise Riba-based financing or prohibited repurchase arrangements.
• Binding bilateral promises are exceptional and mainly justified by genuine commercial necessity.
• Master agreements establish frameworks for future transactions but do not themselves create those transactions.
• The framework seeks to balance commercial certainty with genuine ownership, risk-sharing, fairness, and Shariah integrity.

Understanding promises in Islamic Finance ultimately means understanding the difference between an intention to transact and the transaction itself. This distinction protects contractual authenticity while allowing modern commerce to function efficiently and ethically.