https://en.wikipedia.org/wiki/Armando_Valladares

Valladares is from Pinar del Rio, Cuba.[4] By his own account, he was initially a supporter of Fidel Castro's Cuban Revolution, later becoming an employee of the Office of the Ministry of Communications for the Revolutionary Government, for which he worked at a post office.[4][5]
In 1960, at the age of 23, he reportedly refused to put an "I'm with Fidel" sign on his desk at work.[5] Shortly after, he was arrested by political police at his parents' home.[6] He was subsequently given a thirty-year prison sentence.[4] The Cuban government stated that his arrest was on charges of terrorism, and that he had previously worked for the secret police of Fulgencio Batista's dictatorship.[7] The international human rights organizations Oslo Freedom Forum, PEN International, and Amnesty International, in contrast, stated their belief that Valladares had been imprisoned solely for his anti-Castro stance, and the latter organization named him a prisoner of conscience.[3][5][8]

http://www.becketfund.org/armando-valladares-speech/
I am not an extraordinary man, and I am quite ordinary. But God chose me for something quite extraordinary.

When I was 23 years old I refused to do something that at the time seemed very small. I refused to say a few words, “I’m with Fidel.” First I refused the sign on my desk at the postal office that said that, and after years of torture and watching many fellow fighters die, either in body or in spirit, I still refused to say those words.

If I just said those three words, I would have been released from prison.

My story is proof that a small act of defiance can mean everything for the friends of liberty. They did not keep me in jail for 22 years because my refusal to say three words meant nothing. In reality those three words meant everything.

For me to say those words would constituted a type of spiritual suicide. Even though my body was in prison and being tortured, my soul was free and it flourished. My jailers took everything away from me, but they could not take away my conscience or my faith.

Even when we have nothing, each person and only that person possesses the key to his or her own conscience, his or her own sacred castle. In that respect, each of us, though we may not have an earthly castle or even a house, each of us is richer than a king or queen.

…

For many of you, particularly the young people, it may seem I come from a faraway land from a long time ago. Young friends, you may not be taken away at gunpoint, as I was for staying true to my conscience, but there are many other ways to take you away and to imprison your body and your mind. There are many ways you can be silenced, in your schools, your universities, in your workplace.

I warn you: Just as there is a very short distance between the US and Cuba, there is a very short distance between a democracy and a dictatorship where the government gets to decide what to do, how to think, and how to live. And sometimes your freedom is not taken away at gunpoint but instead it is done one piece of paper at a time, one seemingly meaningless rule at a time, one small silencing at a time. Never allow the government–or anyone else–to tell you what you can or cannot believe or what you can and cannot say or what your conscience tells you to have to do or not do.