It's the second treatise concerning civil government. The state of nature has a law of nature to govern it, which obliges everyone. And reason, which is that law, so reason is the law of nature to govern it, 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. And 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. Now to parse what he's saying, he says that reason is this natural law that should govern human action. And he's saying no one ought to harm anyone else and that if we're not in competition, maybe there's only enough food for one of us and there's two of us there, in which case we'd be in competition, but if there isn't that competition, we should be trying to help each other and we should be trying to preserve the rest of mankind. And unless it's for the purpose of justice, you don't have the right to take away or impair the life or things that help preserve the life, the liberty, the health, limb, or goods of another.