it is impossible, since fasting yesterday has already passed. Likewise, if a child says, “I owe Allah a vow to fast,” it is not binding either, and thus does not fall under the valid type. The author’s words, “The valid type,” exclude that which has not become binding, for that which has not become binding has no legal ruling.
His statement, “The unrestricted type—for example, when one says, ‘I owe Allah a vow,’ without specifying anything; then he must offer the expiation for an oath”: this is the first category. “Unrestricted” means that nothing has been specified in it: he merely says, “I owe Allah a vow.” We call it unrestricted because he has not specified anything.
For example, a man says, “I owe Allah a vow,” whether or not he had intended to specify something. He may say, “I owe Allah a vow,” while intending inwardly to specify something, but then change his mind and say nothing further. Or he may not have intended anything at all, simply saying, “I owe Allah a vow.” We say that he must offer the expiation for an oath, based on the Prophet’s statement, peace and blessings be upon him, in the hadith of Uqbah ibn Amir, may Allah be pleased with him: “The expiation for a vow when it is not specified is the expiation for an oath.” Narrated by Ibn Majah (1). Muslim also narrated it, without the words “when it is not specified,” with the wording: “The expiation for a vow is the expiation for an oath.” (2)
The expiation for an oath is to feed ten needy people, clothe them, or free a slave. If he cannot find the means, then he must fast three consecutive days.