Free expression is the base ...

Free expression is the base of human rights, the root of human nature and the mother of truth. To kill free speech is to insult human rights, to stifle human nature and to suppress truth.
Free expression is the base of human rights, the root of human nature and the mother of truth. To kill free speech is to insult human rights, to stifle human nature and to suppress truth.
 Liu Xiaobo

More phrases

All the great things are simple, and many can be expressed in a single word: freedom, justice, honor, duty, mercy, hope.
I know but one freedom and that is the freedom of the mind.
 Antoine de Saint-Exupéry
Freedom is not worth having if it does not connote freedom to err.
The amount of happiness that you have depends on the amount of freedom you have in your heart.
 Thích Nhất Hạnh
Without freedom of thought, there can be no such thing as wisdom - and no such thing as public liberty without freedom of speech.

Quotes from the same author

Hatred is corrosive of a person's wisdom and conscience; the mentality of enmity can poison a nation's spirit, instigate brutal life and death struggles, destroy a society's tolerance and humanity, and block a nation's progress to freedom and democracy.
 Liu Xiaobo
Freedom of expression is the foundation of human rights, the source of humanity, and the mother of truth.
 Liu Xiaobo
The free world led by the U.S. fought almost all regimes that trampled on human rights.
 Liu Xiaobo