Legal obligation

The law of obligations is one branch of private law under the civil law legal system and so-called "mixed" legal systems. It is the body of rules that organizes and regulates the rights and duties arising between individuals. The specific rights and duties are referred to as obligations, and this area of law deals with their creation, effects, and extinction.

An obligation is a legal bond (vinculum iuris) by which one or more parties (obligants) are bound to act or refrain from acting. An obligation thus imposes on the obligor a duty to perform, and simultaneously creates a corresponding right to demand performance by the obligee to whom performance is to be tendered. Obligations may be civil, which are enforceable by action in a court of law, or natural, which imply moral duties but are unenforceable unless the obligor consents.

Justinian first defines an obligation (obligatio) in his Institutiones, Book 3, section 13 as "a legal bond, with which we are bound by necessity of performing some act according to the laws of our State." He further separates the law of obligations into contracts, delicts, quasi-contracts, and quasi-delicts.

Nowadays, obligation, as applied under civilian law, means a legal tie (vinculum iuris) by which one or more parties (obligants) are bound to perform or refrain from performing specified conduct (prestation). Thus an obligation encompasses both sides of the equation, both the obligor's duty to render prestation and the obligee's right to receive prestation. It differs from the common-law concept of obligation which only encompasses the duty aspect.

Every obligation has four essential requisites otherwise known as the elements of obligation. They are:

Obligations arising out of the will of the parties are called voluntary, and those imposed by operation of law are called involuntary. Sometimes these are called conventional and obediential. The events giving rise to obligations may be further distinguished into specified categories.

A contract can be broadly defined as an agreement that is enforceable at law. Gaius classified contracts into four categories which are: contracts consensu, verbal contracts, contracts re, and contracts litteris. But this classification cannot cover all the contracts, such as pacts and innominate contracts; thus, it is no longer used.

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