From the four-hour “I am prepared to die” speech he gave at his 1962 trial to letters written after his retirement, Nelson Mandela’s thoughts and words of wisdom have long inspired people around the world. On what would have been his 99th birthday, here are some of Madiba’s most thought-provoking and inspirational words.

1. ON COURAGE:

"I learned that courage was not the absence of fear, but the triumph over it. The brave man is not he who does not feel afraid, but he who conquers that fear."

The Long Walk to Freedom, 1994

2. ON GROWTH:

"It is in the character of growth that we should learn from both pleasant and unpleasant experiences.”

Address to the Foreign Correspondents Association, 1997

3. ON LEARNING FROM THE PAST:

“Out of the experience of an extraordinary human disaster that lasted too long, must be born a society of which all humanity will be proud.”

Presidential inauguration, 1994

4. ON ACHIEVING SUCCESS:

“Everyone can rise above their circumstances and achieve success if they are dedicated to and passionate about what they do.”

—A letter to South African cricket player Makhaya Ntini, 2009

5. ON PARENTING:

“Few things make the life of a parent more rewarding and sweet as successful children.”

Letter from prison, 1981

6. ON HUMANITY:

“Men, I think, are not capable of doing nothing, of saying nothing, of not reacting to injustice, of not protesting against oppression, of not striving for the good society and the good life in the ways they see it.”

Statement to the court, 1962

7. ON UNITY:

“We must embrace one another on the basis of justice and nurture the extended family to which we all belong.”

Speech at anti-Apartheid activist Beyers Naude's 80th birthday celebration, 1995

8. ON PERSISTENCE:

“But I have discovered the secret that after climbing a great hill, one only finds that there are many more hills to climb.”

The Long Walk to Freedom, 1994

9. ON MEETING CHALLENGES:

"Difficulties break some men but make others. No axe is sharp enough to cut the soul of a sinner who keeps on trying, one armed with the hope that he will rise even in the end."

Letter to Winnie Mandela, 1975

10. ON INTEGRITY:

“Those who conduct themselves with morality, integrity and consistency need not fear the forces of inhumanity and cruelty.”

—British Red Cross Humanity lecture, 2003

11. ON EQUALITY:

“I have never regarded any man as my superior, either in my life outside or inside prison.”

Letter written from prison to the Prison Commissioner, 1976

12. ON OPTIMISM:

“Part of being optimistic is keeping one's head pointed toward the sun, one's feet moving forward.”

Long Walk to Freedom, 1994

13. ON EDUCATION:

“Education is the most powerful weapon which you can use to change the world.”

Speech from the launch of the Mindset Network, 2003

14. ON LIVING LIFE FULLY:

"There is no passion to be found playing small—in settling for a life that is less than the one you are capable of living."

Long Walk to Freedom, 1994

15. ON BELIEFS:

“One cannot be prepared for something while secretly believing it will not happen.”

Long Walk to Freedom, 1994