Wolfhart Pannenberg differentiates a number of stages in the development of western notions of "freedom" from its early Christian associations. He writes:
"Very much at the heart of modern culture we find ambiguities that result from a sometimes curious admixture of Christian and non-Christian ideas. The most important example is the modern idea of freedom. There is clearly a Christian root in the belief that all human persons are born to be free and that such freedom should be respected. There is the biblical teaching that human beings are created in the image of God and created to enjoy communion with God. In fact, it is only communion with God that actually makes us free, according to Jesus (John 8:36) and Paul (2 Corinthians 3:17). While every human being is created to enjoy the freedom that comes from communion with God, it is only in Christ that such freedom is fully realized through redemption from sin and death. Such is the Christian idea of freedom.It must be conceded that John Locke's natural law theory is only a thin ghost of the more substantial understandings of natural law that preceded him. The Scholastics believed that even though man's fixed essence and natural end derive ultimately from God, we can nevertheless infer from this essence and natural end a doctrine of natural law and human rights without appealing directly to God's will. But as Jeremy Waldron (by no means a religious right-winger) notes in his book, God, Locke, and Equality, John Locke was an Enlightenment-era Protestant who abandoned the medieval Scholastic notions of an objective human essence and natural ends, and, with them, the traditional basis of belief in natural law and natural human rights. The question he faced, then, was the serious problem of how to justify belief in human equality. His solution was to appeal to the idea that even if there are no fixed limits to human nature, human beings at least have the ability to reason, which is adequate to lead them to belief in God, and thus -- in a roundabout way -- to grasp the idea that they are His creatures and therefore responsible to Him for how they treat others. Hence, Locke had nothing left but God's will to which to appeal, since, in his view, we can't know anything about human nature as such that will tell us that we have any rights. We are thus thrown back on the knowledge that we are God's property -- that we belong to Him -- and thus that we would be violating His rights if we harmed one another. For this reason, Locke abhorred atheism. This is often forgotten. Although Locke is often celebrated as the preeminent theorist of religious toleration in early modern philosophy, he emphatically denied that toleration could be extended to atheists, for he regarded atheism as a cancer that would undermine the very possibility of any justifiable belief in equal human rights.
"The modern idea of freedom, most effectively proposed by John Locke, differs from the Christian view in that it focuses only on the natural condition of man. It differs also in drawing upon ancient Stoic ideas of natural law. The Stoics taught that the original freedom and equality of human beings in the state of nature was lost because of the necessities of living in society. Locke thought that the Reformation doctrine of the freedom of the Christian made it possible to reclaim the original freedom as an actuality in this life. In contrast to later libertarian views of individual freedom, Locke believed that pure freedom is necessarily united with reason and therefore positively related to law. In Locke's position there is an echo of the Christian understanding that freedom depends on being united with the good and, therefore, with God.
"The prevailing idea of freedom in our societies today, of course, is the idea that each person has the right to do as he pleases. Freedom is not connected to any notion of the good as constitutive of freedom itself. Because of the incompleteness of human existence in history, any idea of freedom involves the risk of abuse. But it does make a very big difference whether the distinction between the use and abuse of freedom is observed. When it is observed, it is possible to challenge the equation of freedom with license. The ambiguity built into the modern idea of freedom helps us understand secular culture's ambivalence when it comes to values in general, and our cultural nervousness about affirming the contents and standards by which the culture itself is defined. With respect to values and cultural traditions, as with truth claims, a consumerist attitude prevails. Each chooses according to his preferences or perceived needs. The disengagement of the idea of freedom from an idea of the true and the good is the great weakness of secularist societies." (Wolfhart Pannenberg, "How to Think About Secularism," First Things (June/July 1996), p. 62.)
I am not here defending Locke's theory of natural law, but pointing out its deficiencies. The Aristotelian conception of a common human essence or nature, coupled with the Judeo-Christian conception that this human nature is created bearing God's very image, serves as the most powerful imaginable foundation for natural human rights and for a system of civil rights based upon it. Take away either notion, and what basis for human rights have you left? The best you may be able to do is some analogue of John Locke's notion, or the broader Protestant Divine Command theory, which bears the clear stamp of late medieval nominalism and voluntarism -- and the potential arbitrariness of the potestas Dei absoluta, with the potential for translating into the abritrariness of the Prince or state Leviathan. But as the track record of the philosophies from those periods shows, they veer precipitously toward the arbitrary will of those who happen to be in power, as seen in Thomas Hobbes' deft gesture of basing what he called 'natural law' upon the positive law of the state!
An adequate understanding of freedom can never be divorced from an apprehension of the good, which requires an apprehension of the nature of things, including human nature. If we are Christians, we know that true self-knowledge comes only through knowledge of God, not only because He is our highest good and end, but because He reveals to us the truth about our own nature and its true good. Hence, the fullest, richest, truest, most personally liberating sense of 'freedom' is found in slavery to Christ our King. Paul knew this. Many of us understand this. Just as the beginning of wisdom is found in something most people find counter-intuitive (to wit--fear: the 'fear of the Lord'), so freedom is found in something most people find counter-intuitive (to wit--slavery: 'slavery to Christ').