state of society, all contracts of men receive a relative, and not a positive interpretation. The state construes them, the state applies them, the state controls them, and the state decides, how far the social exercise of the rights, they give over each other, can be justly asserted.[1] Again, it has been said, that the constitution distinguishes between a contract, and the obligation of a contract. The latter is the law, which binds the parties to perform their agreement. The law, then, which has this binding obligation, must govern and control the contract in every shape, in which it is intended to bear upon it.[2] Again, it has been said, that the obligation of a contract consists in the power and efficacy of the law, which applies to, and enforces performance of it, or an equivalent for non-performance. The obligation does not inhere, and subsist in the contract itself, proprio vigore, but in the law applicable to the contract.[3] And again, it has been said, that a contract is an agreement of the parties; and if it be not illegal, it binds them to the extent of their stipulations. Thus, if a party contracts to pay a certain sum on a certain day, the contract binds him to perform it on that day, and this is its obligation.[4]
§ 1373. Without attempting to enter into a minute examination of these various definitions, and explanations of the obligation of contracts, or of the reasoning, by which they are supported and illustrated; there are some considerations, which are pre-supposed by all