On April 4, 1968 — exactly 49 years ago today — one of the most peaceful and peace-promoting leaders history had ever known was met by a violent death.

The Reverend Dr. Martin Luther King, Jr., a Nobel Peace Prize winner, was shot and killed at the Lorraine Motel in Memphis, Tennessee, at the age of 39.

Today, as the world grapples with the lasting effects of racism and a troubling increase in racially-motivated violent incidents across the United States, King’s optimism, his insistence on peace, and his inspiring message to bring about change to make the world a better place are more urgent than perhaps any time since he was murdered.

Tomorrow...The 49th anniversary of the day Daddy died. I pray that the commemoration cultivates courage and lifts us to love. #MLKpic.twitter.com/X1RUrES2T4

— Be A King (@BerniceKing) April 4, 2017

To honor the life of MLK Jr. and to celebrate his legacy of peace, here are some of  the civil rights leader’s best quotes that speak to the problems of today’s world.   

“All we say to America is be true to what you said on paper. Somewhere I read of the freedom of assembly, somewhere I read of the freedom of speech, somewhere I read of the freedom of press, somewhere I read that the greatness of America is the right to protest. Our right.”

Delivered the day before he was shot and killed, this speech was known as King's "I've Been to the Mountaintop" speech. It was delivered at the Mason Temple in Memphis.

10. "We must learn to live together as brothers or perish together as fools."

In June, 1965, King delivered the commencement address at Oberlin College in Ohio titled "Remaining Awake Through a Great Revolution." He gave students this advice.

9. "The ultimate weakness of violence is that it is a descending spiral, begetting the very thing it seeks to destroy."

Excerpted from King's book, Where Do We Go From Here? Chaos or Community.

8. "Darkness cannot drive out darkness: Only light can do that. Hate cannot drive out hate: Only love can do that."

From King's book, Strength to Love.

7. "Our scientific power has outrun our spiritual power. We have guided missiles and misguided men."

This, too, appeared in King's book Strength to Love, a collection of his sermons. 

6. "Was not Jesus an extremist in love?"

This line appeared in King's 1963 "Letter from a Birmingham Jail," one of the most famous texts he ever wrote and well worth a full read.

5. "People fail to get along because they fear each other; they fear each other because they don't know each other; they don't know each other because they have not communicated with each other."

This quote comes from an advice column King wrote in Ebony magazine in 1958. 

4. "There comes a time when one must take a position that is neither safe nor politic nor popular, but he must take it because his conscience tells him it is right."

In the last year of his life King frequently spoke out against the Vietnam War. This line came from a 1968 speech in Washington, D.C., called "A Proper Sense of Priorities."  

3. "Nothing in the world is more dangerous than sincere ignorance and conscientious stupidity."

Another lasting quote from the sermon collection Strength of Love.

2. "Intelligence plus character—that is the goal of true education."

This is a gripping line these days, amid ongoing political arguments about the role of public education, from King's  “The Purpose of Education." It was a piece he wrote in 1947 for the Morehouse College student newspaper, the Maroon Tiger.

1. “Now I’m not one to lose hope. I keep on hoping. I still have faith in the future.”

Just a year before he was gunned down, King gave an interview to NBC News in 1967 in which he said that maybe, during his "I Have a Dream" days, he was too optimistic, and that life had made him more realistic. Still, he said, he clung to hope and faith in the future. He went on:

"I feel that nonviolence is really the only way that we can follow, cause violence is just so self-defeating. A riot ends up creating many more problems for the Negro community than it solves. You can through violence burn down a building, but you can’t establish justice. You can murder a murderer, but you can’t murder murder through violence. You can murder a hater, but you can’t murder hate. And what we’re trying to get rid of is hate and injustice and all of these other things that continue the long night of man’s inhumanity to man."