(ABC News) -- Martin Luther King Jr., whose assassination was 50 years ago this week, was known for his soaring oratory as well as his leadership of the U.S. civil rights movement.

Here are some inspirational quotes from the minister and civil rights leader who was gunned down in Memphis on April 4, 1968:

1. "Injustice anywhere is a threat to justice everywhere." (Letter from Birmingham City Jail)

2. "If a man hasn't discovered something he will die for, he isn't fit to live.” (Preview of the “Dream” at Detroit March)

3. “As long as there is poverty in this world, no man can be totally rich even if he has a billion dollars.” (“The American Dream”)

4. "Negroes of the United States, following the people of India, have demonstrated that nonviolence is not sterile passivity, but a powerful moral force…" (Nobel Prize Acceptance Speech)

5. “Civilization and violence are antithetical concepts.” (Nobel Prize Acceptance Speech)

6. “Everybody can be great ... because anybody can serve. You don’t have to have a college degree to serve. You don’t have to make your subject and verb agree to serve. You only need a heart...” (“The Drum Major Instinct,” Ebenezer Baptist Church)

7. “We are caught in an inescapable network of mutuality, tied in a single garment of destiny. Whatever affects one directly, affects all indirectly.” (Letter from Birmingham City Jail)

8. “We must use time creatively, in the knowledge that the time is always ripe to do right.” (Letter from Birmingham City Jail)

9. “Somewhere we must come to see that human progress never rolls in on the wheels of inevitability. It comes through the tireless efforts and persistent work of dedicated individuals...” (Oberlin College Commencement)

10. “Mankind must put an end to war or war will put an end to mankind.” (Oberlin College commencement)

The nation honors Martin Luther King’s memory annually on the third Monday of January around his birthday, January 15.