on the stipulated condition, and is therefore not bound by the sale without it but has the option to rescind, so too the other party consented only to the stated price, even though he accepted that price together with the condition. If the condition is set aside and the right of patronage belongs to him, he has not thereby consented to pay more than the stated price. Rather, he may rescind the sale if he wishes; he cannot be compelled to pay an additional amount. If he pays the price, the other party may either accept it and uphold the sale or rescind it. If they mutually agree on compensation, that is permissible, but neither may be compelled to accept it without his consent, for it constitutes payment in exchange for the missing component.

The same applies to comparable cases, such as when a transaction is divided. It has been said that the sale remains valid for the lawful portion at its proportional share of the price, as is the apparent position of Ahmad’s school. The party whose transaction has been divided may rescind it if he agreed to sell this portion at its proportional price only together with the other portion.

The fundamental principle governing contracts is that a person is bound only by an obligation he has undertaken himself or one imposed upon him by the Lawgiver. What he has undertaken is what he has pledged to do, so he must neither break his pledge nor act treacherously. What the Lawgiver has commanded him to do is something Allah has obliged him to observe, even if he has not undertaken it himself. Thus, Allah has obliged him to maintain what He has commanded to be maintained, including faith in the Scriptures and the messengers, and the ties of kinship.

For this reason, Allah mentions both in His Book, as when He says:

“Those who fulfill the covenant of Allah and do not break the contract.”

“And those who join that which Allah has ordered to be joined.”