but the contract is not invalidated merely by his claim that he was under legal restrictions.

If he says, “The creditor knows that I was under legal restrictions,” he may require the creditor to swear an oath. Likewise, if he claims coercion, he may require the creditor to swear an oath.

He—may Allah have mercy on him—was asked:

A guarantor is required by the ruler to pay money in connection with wedding celebrations involving certain objectionable practices, such as free women singing to non-mahram men and the like. If the ruler orders that activity stopped, he stops it but demands from the guarantor the money he undertook to pay only in connection with that activity, since the guarantee became binding on that account. The person on whose behalf the guarantee was given believes that this was not included in the guarantee, while the guarantor believes that it was, since those who preceded him customarily included it in their guarantees, and the guarantee was concluded on the basis of the previously prevailing circumstances and customary practice.

He replied:

Wronging the guarantor by demanding from him something he does not owe under the contract he entered into—even if that contract is unlawful—is more strictly prohibited than a non-mahram woman singing to men. This is because injustice is prohibited both by reason and by Islamic law, whereas this singing was prohibited only because it may lead to unlawful sexual intercourse, just as looking at a non-mahram woman was prohibited. Moreover, there is an anomalous dissenting opinion concerning it, and the Companions used to listen to the singing of slave women at