nelson mandela

Freedom fighter, human rights advocate, prisoner, and all-around remarkable human Nelson Mandela was South Africa's first black president and first post-apartheid leader.

Not only did Mandela fiercely advocate on behalf of South Africans of color, he gave up decades of his life to do it. His visionary actions against South Africa's racist policies led to a 27-year imprisonment on Robben Island.

Photo by Stephen Jaffe/AFP/Getty Images.

Mandela's actions — from protesting to collaborating with like-minded revolutionaries to his nearly 30-year prison sentence — have been well-documented. But the world didn't know the details of his time in prison — until now.

On July 18, The New York Times is publishing hundreds of unreleased letters from Mandela to coincide with what would have been his 100th birthday.

In "The Prison Letters of Nelson Mandela," over 250 letters to his family, friends, and colleagues reveal some of Mandela's thoughts and emotions during a turbulent time in his life.

Here are five of the key takeaways from collection excerpts:

1. Peace and harmony are possible.

Mandela held onto his faith and spirituality as a source of inspiration to continue fighting for the world he believed in. He wrote of the parts of the Bible that resonated with him strongest:

"The importance of the passages ... lies in the fact that they tell us of a way of life which would have brought us peace and harmony many centuries ago, if mankind had fully accepted and faithfully practiced the teachings they contain.

They visualize a new world where there will be no wars, where famine, disease, and racial intolerance will be no more, precisely the world for which I am fighting … "

2. There is a time for civility and kindness, and there is a time to fight for change.

Prioritizing civility and kindness is important, but there are always times when one must stand up for what is right. Mandela offered some blatant, important truths, noting that while one person is powerful, a group of people committed to a just cause can move mountains:

"It's a good thing to help a friend whenever you can; but individual acts of hospitality are not the answer. Those who want to wipe out poverty from the face of the earth must use other weapons, weapons other than kindness.

This is not a problem that can be handled by individual acts of hospitality. The man who attempted to use his own possessions to help all the needy would be permanently ruined and in due course himself live on alms. Experience shows that this problem can be effectively tackled only by a disciplined body of persons, who are inspired by the same ideas and united in a common cause."

Photo by Trevor Samson/AFP/Getty Images.

3. Humans are complex and resilient.

In a letter to his wife Winnie, Mandela discussed his attempts to find solace in solitary confinement and described the complexity of the human experience — including our capacity for resilience:

"Honesty, sincerity, simplicity, humility, pure generosity, absence of vanity, readiness to serve others — qualities which are within easy reach of every soul — are the foundation of one's spiritual life.

Never forget that a saint is a sinner who keeps on trying. … No ax is sharp enough to cut the soul of a sinner who keeps on trying, one armed with the hope that he will rise and win in the end."

Good people make mistakes, but the determination to do good prevails.

4. There is power in unwavering hope.

In another letter to Winnie, Mandela made an impassioned plea to use hope in the face of adversity. Having read the work of Dr. Norman Vincent Peale, Mandela expressed his unshakable belief in the power of positive thinking:

"The man who says: I will conquer this illness and live a happy life, is already halfway through to victory. … Remember that hope is a powerful weapon even when all else is lost.

You and I, however, have gained much over the years and are making advances in important respects. You are in my thoughts every moment of my life. Nothing will happen to you, darling. You will certainly recover and rise."

Photo by Walter Dhldhla/AFP/Getty Images.

Nelson Mandela's letters reveal a man who was nuanced, thoughtful, and determined to do good. In our changing, complex society, his words offer important insights on how to continue fighting for a better world.