Vows

Q1: What is a vow?
A1: Vow (Nadhr) means making it obligatory upon oneself to do some good act, or to refrain from doing an act, which it is better not to do, for the sake of, or for the pleasure of Allah.
Q2: If a woman wants to make a religous vow, does she need her husband's permission?
A2: Yes, she does.
Q3: How many kinds of vows are there? Please, explain.
A3: First, conditional vow, for example, one says: “If my patient recovers from his/her ailment, it will be obligatory upon me to do a certain act for the pleasure of Allah.” This is called “Nadhr Shokr” or “thanking vow”, or “if I do a certain bad action, I shall perform certain good action for the pleasure of Allah,” and this is called “Nadhr Zajr” or “punishment vow”.
Second, absolute or unconditional vow; in this case, one should say without any conditions: “I make a Nadhr (vow) for the pleasure of Allah to offer night prayers.” And all of these vows are correct.