Show me where Locke believes that in a state of nature people are "bound by certain rules", particularly in regard to violation of property rights.
Chapter 2, "Of The State of Nature," section 6:
But though this be a state of liberty, yet it is not a state of licence: though man in that state have an uncontroulable 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
Locke believed that government was necessary for the protection of property rights.
This proceeds too quickly: Locke though that government was necessary to protect property rights
whilst also avoiding the "inconveniences" of leaving that protection up to the individual himself. But his argument about these inconveniences was fallacious: he said that people couldn't be trusted to judge in their own cases, and therefore require an independent and impartial third party to judge for them, and to reach a final resolution. However, two responses can be made to this:
1) The need for an independent and impartial third party does not imply that everybody needs the same independent and impartial third party to resolve their disputes. It is no more logically the case that because everybody needs an independent and impartial third party thate there is an indpendent and impartial third party everybody needs than it would be to claim that because everybody likes at least one TV program, there is at least one TV program everybody likes. You and I could have our dispute resolved by A, and yet Alex Free Market and free agent can have their dispute resolved by B.
2) The argument that there needs to be an independent and impartial third party to achieve a final verdict in a dispute is an argument
against government, not for it: This is because one party in a dispute could be the government itself. But if the government itself is supposed to be the final authority, with a monopoly on ultimate resolution of disputes and use of legitimate force, then so long as government exists, there can be no independent and impartial third party in disputes with it.
On these issues, I reccomend you check out
this informal talk by Roderick Long, which is transcribed
here.
The "obligation" in Locke's world is enforced by government. I think nearly everyone believes there is a moral obligation to not initiate force on others, but certain people do not follow that obligation at certain times, and I believe that in these cases a government is necessary to provide justice for those aggressed against.
I don't see why government is necessary even in these cases, and I don't see it for the simple reason that it would be bizarre to say that a government is just
any government that protects people from agression, or provides protection under the law. After all, security firms do this, too. In fact, as an Englishman,
I have the same rights of arrest as any policeman does, and can make a citizen's arrest. So it is clear that not just every institution that protects people's rights under the law is a government.
But, if being an institution that protects people's rights under the law is
insufficient for said institution to be a government, it follows that the fact that we need such institutions does not prove that we need a government.