Natural law does not depend directly on God’s will. Natural law goes back to at least the scholastics and perhaps Thomas Aquinas. Modern Natural Rights theory began in 1625. Modern theory recognizes the institution the state. Natural law is thought to produce inalienable natural rights. They speak to the dignity of the individual and life and property. The close connection between liberty and property is part of this tradition.
John Locke changed in 1689 the notions of the origin of private property. Locke’s doctrines became the basis of classical liberalism and libertarianism. The original acquisition had to be legitimate. Every man has a property in his own person. Self-ownership and homesteading were the foundation of private property. No natural rights are given up when individuals enter political society. You have the right to be protected by the government and the right to protect yourself from the government. You cannot divest yourself of these rights.
In 1982 The Ethics of Liberty by Murray Rothbard took up Natural Rights.