Such a conditional vow is exemplified by someone’s saying, “If Allah saves me from such-and-such, then I must do such-and-such,” naming a particular offering or act of obedience to Allah. The same applies when he says, “If Allah allows me to reach such-and-such, or reunites me with so-and-so, then I must perform such-and-such act of worship.” The vow becomes binding if he is able to fulfil it; if he is unable, he must wait until he becomes able.
As for a vow that entails disobedience, it is like a person’s statement: “It is incumbent upon me for Allah’s sake to commit fornication, or to steal, or to drink wine, or to kill such-and-such Muslim without right,” or any other sin, whether minor or major. Whoever utters such a vow is not permitted to do any of it, and nothing—neither an expiation nor anything else—is required of him for refraining from it.
A vow is invalid with respect to something a person does not own, except when he says, “It is incumbent upon me for Allah’s sake that, if I should come to own so-and-so—the slave of another—I will set him free,” or, “If Allah heals me, restores my health, or brings me back safely from my journey and I then acquire ownership of so-and-so, I will manumit him.” In such cases the vow is binding, and Imam Mālik does not regard this as belonging to the category of vows concerning what a human being does not yet own.
If someone vows an act of obedience on condition that he commit a sin, the act of obedience does not become obligatory, nor is he allowed to commit the sin. An example is his saying, “If I drink wine, I must give such-and-such in charity.” It is forbidden for him to drink wine, and the charity is not due; but if he does drink, he is subject to the ḥadd punishment and the charity then becomes binding.
Conversely, if he vows an act of obedience on the condition that he refrain from a sin, the obedience becomes binding and he is still forbidden to commit the sin. Should he nonetheless commit the sin, the obedience that he had linked to its absence lapses. An example is his saying, “It is incumbent upon me before Allah to give a dirham—or a dinar—in charity if I do not drink wine today.” In that case both the charity and abstaining from wine are obligatory; but if he drinks, the charity drops while he incurs sin and the ḥadd.
If he obligates himself to one act of obedience conditional upon performing another act of obedience, he has a choice: if he performs the first, the second becomes binding; if he omits the first, the second is not binding. For example, he might say, “If I perform Hajj this year, it is incumbent upon me to give such-and-such in charity; then—"