The first two paragraphs of John Stuart Mill’s On Liberty “Chapter V: Applications” speak for themselves, but I changed the formatting and capitalized “First” to highlight the two maxims. He writes:

I offer, not so much applications, as specimens of application; which may serve to bring into greater clearness the meaning and limits of the two maxims which together form the entire doctrine of this Essay, and to assist the judgment in holding the balance between them, in the cases where it appears doubtful which of them is applicable to the case.

The maxims are, 

1. First, that the individual is not accountable to society for his actions, in so far as these concern the interests of no person but himself. Advice, instruction, persuasion, and avoidance by other people if thought necessary by them for their own good, are the only measures by which society can justifiably express its dislike or disapprobation of his conduct. 
2. Secondly, that for such actions as are prejudicial to the interests of others, the individual is accountable, and may be subjected either to social or to legal punishment, if society is of opinion that the one or the other is requisite for its protection.