Tractate Nedarim is similar to tractates Nazir, Shevuot, and to a degree, Arakhin, in that they all address obligations that are not imposed by the Torah but are voluntarily created by an individual. In a broad sense, the category of vows includes nazirite vows, oaths, and consecrations, which are the primary topics addressed in those tractates. These tractates are connected not only with regard to their general topic but also with regard to the structure of the tractates and the halakhic details that are common to these different manifestations of vows. Tractate Nedarim, which addresses the topic of vows in a more narrow sense, is found in the order of Nashim because most of the verses in the Torah that address this topic refer to vows of women. However, the halakhot apply equally to vows made by anyone.

Most usages of the term vow in the Torah itself refer to vows of consecration, whereby an individual invests an item with sanctity. Conversely, in rabbinic literature, the term vow generally refers to vows of prohibition, whereby one causes a particular item to become forbidden for his use. Nevertheless, vows of prohibition must be understood within the context of vows of consecration.

With regard to the impact of a vow upon people, there is a significant difference between vows of consecration and those of prohibition in that vows of consecration render an item forbidden for use by anyone, whereas vows of prohibition cause an item to be forbidden only for the individuals specified in the vow. One can declare any item to be forbidden for use for himself, and one can declare anything he owns to be forbidden for use by anyone else.

Although vows are taken voluntarily and one does not fulfill a mitzva by taking a vow, once an individual takes one, he is required by Torah law to keep his word. There is a positive mitzva to keep his vow, expressed in the phrase “he shall do according to all that proceeds out of his mouth” (Numbers 30:3), and one violates a prohibition if he breaks his vow, as expressed in the same verse: “He shall not profane his word.” Due to the fact that once one takes a vow the content of his vow is no longer a personal decision but a formal halakhic requirement, there are specific guidelines as to which declarations cause a vow to take effect.

For a vow to take effect, three conditions must be met. First, the individual must intend to take a vow. Next, he must give clear verbal expression to this intent. Finally, there must be an object upon which the vow takes effect, and the vow must be expressed in a way that allows it to apply to that object. If these conditions are not met, the vow does not take effect, at least by Torah law. A large portion of this tractate is dedicated to clarifying each of these conditions and to explaining their relationship to one another.

The intent of the individual making the vow is of great importance with regard to the halakhot of vows, and if everyone could be trusted to recall their intent, vows would be interpreted on the basis of this intent alone. However, there is a halakhic principle that intentions that are not verbalized have no legal standing. Nevertheless, in cases where the intention of the individual is clear to all, his intent is the determining factor even when his verbal statement indicates something different, e.g., in the cases of vows of urging or of exaggeration, discussed at the beginning of the third chapter. At the same time, intent alone does not create a vow; a vow does not take effect unless it is verbalized.

The verbal expression of a vow can lead to questionable situations, e.g., where one did not express his vow clearly and his intention is understood only from context, which is known as an intimation of a vow; where he used substitute terms instead of the terms generally used to express a vow; or when he employed terminology whose precise meaning is unclear. A large portion of tractate Nedarim is dedicated to clarifying unclear terminology, including ambiguous expressions or expressions that can be interpreted in either a limited or a broad manner. In particular, this tractate defines various elements that one might refer to in a vow: different types of foods and other products, groups of people, and dates and times.

Even when the intent and verbal expression of the individual are clear, there are situations in which a vow cannot take effect. These include cases where one declares an item to be like another item that is inherently forbidden rather than forbidden due to a vow. Additionally, a vow can take effect only if it can apply to an item that has concrete substance.

When a vow does take effect, it can apply in a variety of ways. One can cause an item to be forbidden from being eaten, or to become forbidden from having benefit derived from it more generally. The manner in which a vow is expressed indicates whether it is limited to the item specified or whether it applies even to replacement items or to products of the original item. Similarly, it will determine whether the vow applies as long as the item belongs to a particular individual, or whether it continues to apply even if the item later belongs to someone else. Another variable is whether the vow renders a particular item forbidden to the individual making the vow, or whether he is declaring an item that belongs to him to be forbidden to other individuals.

While the halakhot of vows are discussed in the Torah, the Sages did not perceive vows to be a positive phenomenon. This is due to a general perspective that it is not advisable to add new prohibitions to those already mentioned in the Torah, and because vows are generally taken when one is angry or embroiled in dispute and often contribute to the perpetuation of the dispute. Consequently, the Sages recommended dissolving vows.

The possibility of dissolving a vow is not mentioned explicitly in the Torah, but it stems from the very nature of a vow itself. Since a vow stems from the intent of the individual who makes it, when he is no longer interested in the vow, it should no longer be relevant. Nevertheless, one cannot decide on his own that a vow no longer applies; he must submit a request to an ordained judge or to a rabbinical court to dissolve it.

Vows can be dissolved in one of two cases. One case is when there is an opening, i.e., when the judge discovers that the individual did not take into account all of the ramifications of his vow when he originally made it. The other case is due to regret, i.e., the individual regrets ever having made the vow. In these cases the judge can dissolve the vow, abrogating it retroactively.

The Torah also introduces the concept of nullification of vows. A father has the authority to nullify the vows of his daughter until she attains majority. Similarly, a husband can nullify the vows of his wife. If this is done, the vows are not abrogated retroactively but are simply canceled from the time of the nullification. The rights of a father or husband to nullify vows are limited with regard to the time frame for nullification, as they can nullify vows only on the day they hear of them. Additionally, a husband can nullify only vows of affliction or those that directly or indirectly affect the relationship between himself and his wife. According to many opinions, a father is also empowered to nullify only vows of affliction or those that affect his relationship with his daughter. In the case of a young betrothed woman, who is still a member of her father's household, the father and husband must both nullify the vow in order for it to be canceled.

It should be noted that although the Vilna Talmud includes a commentary identified on the page as Rashi, it is generally presumed not to have been written by Rashi himself. This commentary will be referred to in the notes on this tractate as the Commentary on Nedarim. Unlike in other tractates, the commentaries of the Ran and the Rosh are printed on the page of the Vilna Talmud in tractate Nedarim. They are accorded great significance by those who study this tractate. Tractate Nedarim has eleven chapters, some of which address one clearly defined topic, and some of which discuss several topics that are also addressed elsewhere.

Chapter One addresses the topics of substitute terms for vows and intimations of vows.

Chapter Two discusses vows that do not take effect because one associated the object of his vow with an item that did not itself become forbidden by a vow, or because there is no object of his vow that is subject to vows. It also discusses the differences between vows and oaths.

Chapter Three lists vows that do not cause a prohibition because they were not made wholeheartedly. It also defines who is included when one takes a vow that pertains to groups of people.

Chapter Four is concerned with the differences between one who vows not to eat an item and one who vows not to derive benefit from an item. It also clarifies what is permitted to one who vows not to derive benefit from another individual.

Chapter Five clarifies that if one vows not to derive benefit from another individual, it is prohibited for him to derive benefit even from items that are not owned in their entirety by that individual.

Chapter Six defines the terms used to express a vow with regard to various food items.

Chapter Seven explains the meanings of various terms used to express a vow, and the prohibition of items that are replacements for or that have grown from items forbidden by a vow.

Chapter Eight discusses the periods of time one might specify in a vow.

Chapter Nine deals with the dissolution of vows by a judge and the openings necessary to allow their dissolution.

Chapter Ten is concerned with the nullification of vows by a father or husband, including the case of a betrothed woman.

Chapter Eleven clarifies the particulars of the process of the nullification of vows and completes other details concerning the general halakhot of vows.