The concept originated in Ancient Greece, and the very expression ("jus naturale") was coined by Roman lawyers. In Antiquity, natural law was understood as justice existing by nature. It was opposed to real (positive) law as an absolute model. Natural law was conceived as a single, common for all people (sometimes for animals), its source is nature and deity, while positive law is created by people, and each nation has its own. From the Roman jurists, the concept of natural law was assimilated by medieval thought, which began to consider God as its only source, which established it for a happy life in paradise.
"In Modern times, it was emphasized that natural law is reasonable, so that even God could not change it, because that would mean contradicting himself as a Great Mind. Natural law was still seen as the source of both morality and law proper, thus not distinguishing between moral and legal" (Political Science. Edited by B.N. Vasiliev, Moscow, Prospekt, 2003, p. 49). Also, a distinction was not always made between natural law and natural law. Some thinkers (G. Grotius, B. Spinoza) they merge into a single, natural source of positive law and the state. Hobbes and Locke insist that the right is, first of all, the freedom to do or not to do something, while the law is necessary – it commands or forbids. Hobbes, defining natural law, emphasizes that it is "the freedom of every human being to use his own powers at his discretion to preserve his own nature, i.e. his own life." The heiress of such an interpretation of natural law can be considered the modern doctrine of human rights" (Political Science Dictionary. St. Petersburg, "Peter", 2004, p. 77).