Locke posited an initial stage, at some time in the distant past, when men interacted with each other in a state of absolute freedom and equality and he called it the "State of Nature". This state is devoid of an organized society, except for the family unit, and has no prescribed rules of behavior, i.e., no man-made law, except for the authoritarian rules found in the family group. It has been asserted by many that this initial condition – the State of Nature – is a hypothetical concept, since there is no evidence that it has ever prevailed among men long enough to be recognized as a significant factor in men's’ historical development. That could be so. However, there have been instances in history (the "wild West" of 19^th century North America comes to mind) when men have readily adapted to, and instinctively acted in compliance with, what Locke calls the "Law of Nature". Those who do not recognize the Law of Nature would rather call this a lawless, anarchistic society. But few would deny that the expectation of freedom and of rights equal to those of every other man’s in exercising that freedom are innate to all of us.

#5 This equality of Men by Nature, the Judicious Hooker looks upon as so evident in it self, and beyond all question, that he makes it the Foundation of that Obligation to mutual Love amongst Men, on which he Builds the Duties they owe one another, and from whence he derives the great Maxims of Justice and Charity. His words are;

"The like natural inducement, hath brought Men to know that it is no less their Duty, to Love others than themselves, for seeing those things which are equal, must needs all have one measure; if I cannot but wish to receive good, even as much at every Man’s hands, as any Man can wish unto his own Soul, how should I look to have any part of my desire herein satisfied, unless my self be careful to satisfie the like desire, which is undoubtedly in other Men, being of one and the same nature? To have any thing offered them repugnant to this desire, must needs in all respects grieve them as much as me, so that if I do harm, I must look to suffer, there being no reason that others should shew greater measure of love to me, than they have by me, shewed unto them; my desire therefore to be lov’d of my equals in nature, as much as possible may be, imposeth upon me a natural Duty of bearing to themward, fully the like affection; From which relation of equality between our selves and them, that are as our selves, what several Rules and Canons, natural reason hath drawn for direction of Life, no Man is ignorant." Eccl. Pol. Lib. 1.

Richard Hooker was a contemporary of Locke’s, known for his work on Natural Law. Locke cites this statement by Hooker in support of the argument that our laws and morals (do unto others as you would have them do unto you) are based on the Law of Nature. It "imposes on me a natural Duty" to love others equally as I love myself. Without recourse to man-made law, I know with my innate natural reason that there are "Rules and Canons" that I and every other human being should observe.

#6 But though this be a State of Liberty, yet it is not a State of Licence, though Man in that State have an uncontroleable Liberty, to dispose of his Person or Possessions, yet he has not Liberty to destroy himself, or so much as any Creature in his Possession, but where some nobler use, than its bare Preservation calls for it. The State of Nature has a Law of Nature to govern it, which obliges every one: And Reason, which is that Law, teaches all Mankind, who will but consult it, that being all equal and independent, no one ought to harm another in his Life, Health, Liberty, or Possessions. For Men being all the Workmanship of one Omnipotent, and infinitely wise Maker; All the Servants of one Sovereign Master, sent into the World by his order and about his business, they are his Property, whose Workmanship they are, made to last during his, not one anothers Pleasure. And being furnished with like Faculties, sharing all in one Community of Nature, there cannot be supposed any such Subordination among us, that may Authorize us to destroy one another, as if we were made for one anothers uses, as the inferior ranks of Creatures are for ours. Every one as he is bound to preserve himself, and not to quit his Station wilfully; so by the like reason when his own Preservation comes not in competition, ought he, as much as he can, to preserve the rest of Mankind, and may not unless it be to do Justice on an Offender, take away, or impair the life, or what tends to the Preservation of the Life, the Liberty, Health, Limb or Goods of another.

In the above paragraph Locke states in beautifully concise fashion the main principles of the Law of Nature. The Law of Nature is grounded in Reason. However, it is significant (and brings great satisfaction to enlightened theists) that Locke recognizes the over-all supremacy of "one Omnipotent and infinitely wise Maker", one "Sovereign Master". Furthermore, Locke recognizes that the Law of Nature places great value on all life and a priority on its preservation, starting with one’s own, unless it need be sacrificed for some "nobler use"; in the case of human life, such sacrifice of one’s life may be called for in war or in a great natural disaster; with respect to "Creatures" in man’s possession, the "nobler use" is for the sustenance of man.

#15 To those that say, There were never any men in the State of Nature; I will not only oppose the Authority of the Judicious Hooker, Eccl. Pol. Lib. 1. Sect. 10. where he says, "The Laws which have been hitherto mentioned, (i.e. the Laws of Nature), do bind Men absolutely, even as they are Men, although they have never any settled fellowship, never any Solemn Agreement amongst themselves what to do or not to do, but for as much as we are not by ourselves sufficient to furnish our selves with competent store of things, needful for such a Life, as our Nature doth desire, a Life, fit for the Dignity of Man; therefore to supply those Defects and Imperfections which are in us, as living singly and solely by our selves, we are naturally induced to seek Communion and Fellowship with others, this was the Cause of Mens uniting themselves, at first in Politick Societies." But I moreover affirm, That all Men are naturally in that State, and remain so, till by their own Consents they make themselves Members of some Politick Society; And I doubt not in the Sequel of this Discourse, to make it very clear.

The Laws of Nature are universal and paramount for all men whether they live in an organized society, or fend for themselves. Men do form societies, the better to seek "a Life, fit for the Dignity of Man" - what Mortimer Adler defines as the necessary components for the attainment of happiness - and in doing so must forego some aspects of the Natural Law for man-made positive law. But the Natural Law is always there to fall back upon, if  positive law loses its authority. 

#16 ... I should have a Right to destroy that which threatens me with Destruction. For by the Fundamental Law of Nature, Man being to be preserved, as much as possible, when all cannot be preserved, the safety of the Innocent is to be preferred: And one may destroy a man who makes War upon him, or has discovered an Enmity to his being, for the same Reason, that he may kill a Wolf or a Lyon; because such Men are not under the ties of the Common Law of Reason, have no other Rule, but that of Force and Violence, and so may be treated as Beasts of Prey, those dangerous and noxious Creatures, that will be sure to destroy him, whenever he falls into their Power.

Paragraph #16 states the Law of Nature in a state of war: one must do everything to preserve oneself and one's people, with priority given to the protection of the "Innocent" - civilians, particularly children. In war, one has the right to destroy one's enemies without reservation.

#17 … he who attempts to get another Man into his Absolute Power, does thereby put himself into a State of War with him; It being to be understood as a Declaration of a Design upon his Life. … no body can desire to have me in his Absolute Power, unless it be to compel me by force to that, which is against the Right of my Freedom, i.e. make me a Slave. … he who makes an attempt to enslave me, thereby puts himself into a State of War with me. He that in the State of Nature, would take away the Freedom, that belongs to any one in that State, must necessarily be supposed to have a design to take away every thing else, that Freedom being the Foundation of all the rest …

The above is a clear and uncompromising statement against slavery. Natural Law grants the right to wage war against the enslaver who, by taking away a man's freedom, robs him of everything.

#18 This makes it Lawful for a Man to kill a Thief, who has not in the least hurt him, nor declared any design upon his Life, any further then by the use of Force, so to get him in his Power, as to take away his Money, or what he pleases from him: because using force, where he has no Right, to get me into his Power, let his pretence be what it will, I have no reason to suppose, that he, who would take away my Liberty, would not when he had me in his Power, take away everything else. And therefore it is Lawful for me to treat him, as one who has put himself into a State of War with me, i.e. kill him if I can …

Paragraph #18 is an unambiguous endorsement of self-defence.  Natural Law justifies the use of whatever force an individual may think necessary ("kill him if I can") to protect both life and property.

#19 … the Law, which was made for my Preservation, where it cannot interpose to secure my Life from present force, which if lost, is capable of no reparation, permits me my own Defence, and the Right of War, a liberty to kill the aggressor, because the aggressor allows not time to appeal to our common Judge, nor the decision of the Law, for remedy in a Case, where the mischief may be irreparable.

Most advanced societies today have surrendered much of this individual's basic natural right of self-defence to the authoritarian rule of positive law. That we as individuals do not have the right to injure or kill the assailant who for all we know intends to kill us, and that we must only evade him and try to summon the police, is the position of the admirer of authority above liberty. Such admiration of authority at the expense of individual liberty is very much a trait of  the conservative's mindset, as well as of the totalitarian's. Locke clearly states that we have the right to do whatever it takes to protect ourselves when the "aggressor allows not time to appeal to our common Judge", i.e. when the law-enforcement agents of the state are not available to protect us.

#22 The Natural Liberty of Man is to be free from any Superior Power on Earth, and not to be under the Will or Legislative Authority of Man, but to have only the Law of Nature for his Rule. The Liberty of Man, in Society, is to be under no other Legislative Power, but that established, by consent, in the Common-wealth, not under the Dominion of any Will, or Restraint of any Law, but what the Legislative shall enact, according to the Trust put in it. Freedom then is not what Sir R. F. tells us, O. A. 55 [224]. "A Liberty for every one to do what he lists, to live as he pleases, and not to be tyed by any Laws": But Freedom of Men under Government, is to have a standing Rule to live by, common to every one of that Society, and made by the Legislative Power erected in it; A Liberty to follow my own Will in all things, where the Rule prescribes not; and not to be subject to the inconstant, uncertain, unknown, Arbitrary Will of another Man. As Freedom of Nature is to be under no other restraint but the law of Nature.

One can marvel at Locke's ability to enunciate, in one short paragraph, how the three basic keystones of a society of free men - Liberty, Rule of Law, Legislative Power by consent of the governed - are interconnected. These ideas constitute the foundations of the constitutions of all modern democratic societies. The wrong and disparaging concept of Liberty quoted above is from one of Locke's ideological adversaries - Sir Robert Filmer, who believed in the divine right of kings.   

#54 Though I have said above, That all Men by Nature are equal, I cannot be supposed to understand all sorts of Equality: Age or Virtue may give Men a just Precedency: Excellency of Parts and Merit may place others above the Common Level: Birth may subject some, and Alliance or Benefits others, to pay an Observance to those whom Nature, Gratitude or other Respects may have made it due; and yet all this consists with the Equality, which all Men are in, in respect of Jurisdiction or Dominion one over another, which was the Equality I there spoke of, as proper to the Business in hand, being that equal Right that every Man hath, to his Natural Freedom, without being subjected to the Will or Authority of any other Man.

Men are not born equal. They are born with unequal talents and abilities, and they have unequal starts in life that depend on the circumstances they are born into. The only equality they share is the right to be free.

#56 Adam was created a perfect Man, his Body and Mind in full possession of their Strength and Reason, and so was capable from the first Instant of being to provide for his own Support and Preservation, and govern his Actions according to the Dictates of the Law of Reason which God had implanted in him. From him the World is peopled with his Descendants, who are all born Infants, weak and helpless, without Knowledge or Understanding. But to supply the Defects of the imperfect State, till the Improvement of Growth and Age hath removed them, Adam and Eve, and after them all Parents were, by the Law of Nature, under an obligation to preserve, nourish, and educate the Children, they had begotten, not as their own Workmanship, but the Workmanship of their own Maker, the Almighty, to whom they were to be accountable for them.

Locke wrote for the people of his time, in the language of the time, in a culture steeped in Judeo-Christian traditions. Locke had the tact to conflate the language of the Enlightenment ( rational reasoning) with that of religious dogma, without in any way debilitating his rational arguments, while placating the religious establishment. Accordingly,  Locke stipulates that God created the prototype Man - Adam, and implanted in him the understanding (or, intelligence) so that he could  "govern his Actions according to the Dictates of the Law of Reason". Parents are obligated, by the Law of Nature, to care for and educate their children so that God's gift to Adam is passed on to posterity.

#57 The Law that was to govern Adam, was the same that was to govern all his Posterity, the Law of Reason. But his Off-spring having another way of entrance into the World, different from him, by natural Birth, that produced them ignorant and without the use of Reason, they were not presently under that Law: for no Body can be under a Law, which is not promulgated to him; and this Law being promulgated or made known by Reason only, he that is not come to use of his Reason, cannot be said to be under this Law; and Adam’s Children being not presently as soon as born, under this Law of Reason were not presently free. For Law, in its true Notion, is not so much the Limitation as the direction of a free and intelligent Agent to his proper Interest, and prescribes no farther than is for the general Good of those under that Law. Could they be happier without it, the Law, as an useless thing would of itself vanish; and that ill deserves the Name of Confinement which hedges us in only from Bogs and Precipices. So that, however it may be mistaken, the end of Law is not to abolish or restrain, but to preserve and enlarge Freedom: For Liberty is to be free from restraint and violence from others which cannot be, where there is no Law: But Freedom is not, as we are told, A Liberty for Every Man to do what he lists: (For who could be free, when every other Man’s Humour might domineer over him?) But a Liberty to dispose, and order, as he lists, his Person, Actions, Possessions, and his whole Property, within the Allowance of those Laws under which he is; and therein not to be subject to the arbitrary Will of another, but freely follow his own.

Children are not able to reason and therefore they are not subject to the Law of Reason.  Until they mature they are under the care of their parents and are not free individuals. One is set free to do as one wishes at adulthood, when the individual has learned the limitations that the Law of Reason imposes on one's actions. One must understand the true meaning of Liberty, which is freedom of action within the allowance of the law.

#87 Man being born, as has been proved, with a Title to perfect Freedom, and an uncontrouled enjoyment of all the Rights and Privileges of the Law of Nature, equally with any other Man, or Number of Men in the World, hath by Nature a Power, not only to preserve his Property, that is, his Life, Liberty and Estate, against the Injuries and Attempts of other Men; but to judge of, and punish the breaches of that Law in others, as he is perswaded the Offence deserves, even with Death it self, in Crimes where the heinousness of the Fact, in his Opinion, requires it. But because no Political Society can be, nor subsist without having in it self the Power to preserve the Property, and in order thereunto punish the Offences of all those of that Society; there, and there only is Political Society, where every one of the Members hath quitted this natural Power, resign’d it up into the hands of the Community in all cases that exclude him not from appealing for Protection to the law established by it. And thus all private judgment of every particular Member being excluded, the Community comes to be the Umpire, by settled standing Rules, indifferent, and the same to all Parties; and by Men having Authority from the Community, for the execution of the Rules, decides all the differences that may happen between any Members of that Society, concerning any matter of right; and punishes those Offences, which any Member hath committed against the Society, with such Penalties as the Law has established: Whereby it is easie to discern who are, and who are not, in Political Society together. Those who are united in one Body, and have a common establish’d Law and Judicature to appeal to, with Authority to decide Controversies between them, and punish Offenders, are in Civil Society one with another: but those who have no such common Appeal, I mean on Earth, are still in the state of Nature, each being, where there is no other, Judge for himself, and Executioner; which is, as I have before shew’d it, the perfect state of Nature.

Paragraph #87 describes the process by which men surrender their "Rights and Privileges of the Law of Nature" to the community when they enter into a Political Society. The individual passes his right to adjudicate and execute the law to the community.

#88 And thus the Commonwealth comes by a Power to set down, what punishment shall belong to the several transgressions which they think worthy of it, committed amongst the Members of that Society, (which is the power of making Laws) as well as it has the power to punish any Injury done unto any of its Members, by any one that is not of it, (which is the power of War and Peace); and all this for the preservation of the property of all the Members of that Society, as far as is possible. But though every Man who has enter’d into civil Society, and is become a member of any Commonwealth, has thereby quitted his power to punish Offences against the Law of Nature, in prosecution of his own private Judgment; yet with the Judgment of Offences which he has given up to the Legislative in all Cases, where he can Appeal to the Magistrate, he has given a right to the Commonwealth to imploy his force, for the Execution of the Judgments of the Commonwealth, whenever he shall be called to it; which indeed are his own Judgments, they being made by himself, or his Representative. And herein we have the original of the Legislative and Executive Power of Civil Society, which is to judge by standing Laws how far Offences are to be punished, when committed within the Commonwealth; and also to determin, by occasional Judgments founded on the present Circumstances of the Fact, how far Injuries from without are to be vindicated, and in both these to imploy all the force of all the Members when there shall be need.

The natural laws that guide the judgement and action of the individual while in the State of Nature are not really abandoned when he enters into a Civil Society. The individual has merely "given a right to the Commonwealth to imploy his force", in the execution of what really would be "his own Judgements, they being made by himself, or his Representative".  Locke notes that this is how the legislative and executive power of civil society arises. 

#89 Where-ever therefore any number of Men are so united into one Society, as to quit every one his Executive Power of the Law of Nature, and to resign it to the publick, there and there only is a Political, or Civil Society. And this is done where-ever any number of Men, in the state of Nature, enter into Society to make one People, one Body Politick under one Supreme Government, or else when any one joyns himself to, and incorporates with any Government already made. For hereby he authorizes the Society, or which is all one, the Legislative thereof to make Laws for him as the publick good of the Society shall require; to the Execution whereof, his own assistance (as to his own Decrees) is due. And this puts Men out of a State of Nature into that of Commonwealth, by setting up a Judge on Earth, with Authority to determine all the Controversies, and redress the Injuries, that may happen to any Member of the Commonwealth; which Judge is the Legislative, or a Magistrate appointed by it. And where-ever there are any number of Men, however associated, that have no such decisive power to appeal to, there they are still in the state of Nature.

The above statement is, of course, an idealistic conception of  how a civil society ought to come into being. It is a model of a democratic society, one that all men should aspire to. We know that in reality few societies have ever approached this model. Most societies have been, and are, stratified to varying degrees into the privileged rulers and the broad multitude of the ruled. Usually, The Law of Nature is encrusted in layers of positive laws that favor specific groups. However, the Lockean model is something we should always strive to attain.

#95 Men being, as has been said, by Nature, all free, equal and independent, no one can be put out of this Estate, and subjected to the Political Power of another, without his own Consent. The only way whereby any one divests himself of his Natural Liberty, and puts on the bonds of Civil Society is by agreeing with other Men to joyn and unite into a Community, for their comfortable, safe, and peaceable living amongst another, in a secure Enjoyment of their Properties, and a greater Security against any that are not of it. This any number of Men may do, because it injures not the Freedom of the rest; they are left as they were in the Liberty of the State of Nature. When any number of Men have so consented to make one Community or Government, they are thereby presently incorporated, and make one Body Politick, wherein the Majority have a Right to act and conclude the rest.

Locke makes the important point that the only way that men can give up their "Natural Liberty and put on the bonds of Civil Society" is by voluntary consent. By implication, if men are coerced against their will to submit to a Political Power, they still retain the right under Natural Law to break the bonds and return to the Liberty of the State of nature.  

#96 For when any number of Men have, by the consent of every individual, made a Community, they have thereby made that Community one Body, with a Power to Act as one Body, which is only by the will and determination of the majority. For that which acts any Community, being only the consent of the individuals of it, and it being necessary to that which is one body to move one way; it is necessary the Body should move that way whither the greater force carrie it, which is the consent of the majority: or else it is impossible it should act or continue one Body, one Community, which the consent of every individual that united into it, agreed that it should; and so every one is bound by that consent to be concluded by the majority. And therefore we see that in Assemblies impowered to act by positive Laws where no number is set by that positive Law which impowers them, the act of the Majority passes for the act of the whole, and of course determines, as having by the Law of Nature and Reason, the power of the whole.

The Law of Nature and Reason guide a self-governing community which has formed by consent of every individual who enters into it. In other words, such government has been founded by unanimous consent of all.  The unanimous consent confers upon the legislature of the self-governing community the power to enact positive laws, by majority decision, that are binding on all citizens.

#97 And thus every Man, by consenting with others to make one Body Politick under one Government, puts himself under an Obligation to every one of that Society, to submit to the determination of the majority, and to be concluded by it; or else this original Compact, whereby he with others incorporates into one Society, would signifie nothing, and be no Compact, if he be left free, and under no other ties, than he was in before in the State of Nature. For what appearance would there be of any Compact? What new Engagement if he were no farther tied by any Decrees of the Society, than he himself thought fit, and did actually consent to? This would be still as great a liberty, as he himself had before his Compact, or any one else in the State of Nature hath, who may submit himself and consent to any acts of it if he thinks fit.

In paragraph #97 Locke elaborates further on the necessity for everyone to accede to the wishes of the majority. If there is no compliance, there is no Compact and no society.

#99 Whosoever therefore out of a State of Nature unite into a Community, must be understood to give up all the power, necessarily to the ends for which they unite into Society, to the majority of the Community, unless they expressly agreed in any number greater than the majority. And this is done by barely agreeing to unite into one Political Society, which is all the Compact that is, or needs be, between the Individuals, that enter into, or make up a Common-wealth. And thus that, which begins and actually constitutes any Political Society, is nothing but the consent of any number of Freemen capable of a majority to unite and incorporate into such a Society. And that is that, and that only, which did, or could give beginning to any lawful Government in the World.

Paragraph #99 declares that the only lawful Government is one constituted by the consent of free men who cede all those rights they have under natural law to the government of the community as may be necessary "to the ends for which they unite into Society".  Such government usually takes a democratic form.