As opposed to tort and unjust enrichment , contract is typically viewed as the part of the law of obligations which deals with voluntary undertakings, and accordingly gives a high priority to ensuring that only bargains to which people have given their true consent will be enforced by the courts. While it is not always clear when people have truly agreed in a subjective sense, English law takes the view that when one person objectively manifests their consent to a bargain, they will be bound.  However, not all agreements, even if they are relatively certain in subject matter, are considered enforceable. There is a rebuttable presumption that people do not wish to later have legal enforcement of agreements made socially or domestically. The general rule is that contracts require no prescribed form, such as being in writing, except where statute requires it, usually for large deals like the sale of land.  In addition and in contrast to civil law systems, English common law carried a general requirement that all parties, in order to have standing to enforce an agreement, must have brought something of value, or " consideration " to the bargain. This old rule is full of exceptions, particularly where people wished to vary their agreements, through case law and the equitable doctrine of promissory estoppel . Moreover, statutory reform in the Contracts (Rights of Third Parties) Act 1999 allows third parties to enforce the benefit of an agreement that they had not necessarily paid for so long as the original parties to a contract consented to them being able to do so.
“Ius Naturale” is the law applicable to men in a state of nature. It precedes religions and kings both in time and in authority. “Ius Naturale” does not derive directly from the will of God. As Hugo Grotius pointed out in the early seventeenth century, even if there was no God, or if God was unreasonable or evil, natural law would still have moral force, and men would still spontaneously back it with physical force. God could not create men as they are, and at the same time make natural law other than what it is. A God that claimed to do that would be a mere tyrant, unworthy of worship.