Muhammad Ali, or formerly Cassius Marcellus Clay, Jr. (1942-2016) led quite a fascinating life and career. 

He was the first fighter to win the world heavyweight championship on three separate occasions. Ali was not just acclaimed for his boxing career, but also for his social activism and profound words.

Here are 10 of Ali's most motivational quotes in honor of his birthday (Jan. 17): 

1. "I hated every minute of training, but I said, ‘Don’t quit. Suffer now and live the rest of your life as a champion."

muhammad ali
Source: ThoughtCo

2. "Impossible is just a big word thrown around by small men who find it easier to live in the world they've been given than to explore the power they have to change it. Impossible is not a fact. It's an opinion. Impossible is not a declaration. It's a dare. Impossible is potential. Impossible is temporary. Impossible is nothing."

muhammad ali,
Source: Si

3. "What you're thinking is what you're becoming."

muhammad ali,
Source: VICE

4. "The fight is won or lost far away from witnesses—behind the lines, in the gym, and out there on the road, long before I dance under those lights."

5. "It isn’t the mountains ahead to climb that wear you out; it’s the pebble in your shoe."

6. "A man who has no imagination has no wings."

muhammad ali, wife,
Muhammad Ali and his wife Source: StarsUnfolded

7. "Live everyday as if it were your last because someday you're going to be right."

muhammad ali, pope,
Source: Mashable

8. "The best way to make your dreams come true is to wake up."

9. "At home I am a nice guy: but I don’t want the world to know. Humble people, I’ve found, don’t get very far."

muhammad ali
Source: Muhammad Ali

10. "He who is not courageous enough to take risks will accomplish nothing in life."