The last time we read Locke he said that in the state of nature we are entirely free, but people joined a contract with each other, constraining their freedom, in order to form a government and enforcement for the sake of protecting everyone’s property from their neighbors. Property included their body. In this reading Locke argues that one cannot choose to become a slave, or legitimately choose to enter a society in which they are a slave. Locke defines a slave as one whose life is always at risk because their master has the ability to kill him or her at any time. To place yourself in this situation is suicidal and irrational because it is placing your ability to sustain yourself at risk, which we all necessarily have a right to do. Locke uses this logic to argue that the only time slavery is acceptable is when one allows someone who deserves to die to live. By not killing them one is only doing them a favor, and they have to choice to get out of the situation at any moment by attempting an escape. If one escapes one survives. If not, one dies.
In this reading Locke defines why we need private property, and where private property came from. When God created the world it was almost entirely empty. God told humans to subdue the earth in order to sustain themselves. The world was entirely shared by all until people started mixing their labor with nature. By picking an apple from a tree someone removed the apple from the state of nature, and turned it into private property, their private property. By using the mixing of labor as the defining action that determined who owned what people did not have to ask each other for permission every time they were hungry, just for the sake of making everything fair, since they were taking from the commons. In that world everyone would starve.
Something becomes my property, assuming it is from the commons, when my horse eats it, my servant trims it, or I dig it from the ground, etc… I break the law of nature when I pick so many apples that I can’t possibly eat them all, and they go bad. This applies to land as well. It is my property as long as I can maintain it, and consume all of the production from it, which could include sharing or training. The key is to prevent it from going to waste. It is not worth being in conflict with my neighbor over land if I cannot even use what I have effectively. Locke recognizes that this assumes that there is plenty of land in the world, such that no one has any justification for envy.
The limits on property get more complicated once humans agreed to start using shiny yellow metal instead of barter. Since money doesn’t spoil, no law of nature prevents one from collecting any amount.
People helped each other grow food and build buildings and tools by mixing their labor with the things in nature.