Steve Jobs.

This sentence comes from Steve Jobs’s speech at Stanford University:

When I was seventeen years old, I read a sentence: “If you spend every day If you live your life as if it were your last day, one day you will find that you are right." This sentence left an impression on me. Since then, after 33 years, I have looked in the mirror every morning and asked myself: "If today was the last day of my life, would you accomplish what you want to do today?" When it's "No", I know I need to change something.

"Remember you are going to die" is the most important motto I have ever encountered in my life. It helped me point out important choices in life. Because almost everything, including all honor, all pride, all fear of embarrassment and failure, will disappear in the face of death. What I saw was the really important stuff left behind. You sometimes think about what you're going to lose, and "remembering that you're going to die" is the best way I know to avoid those thoughts. You are already naked and there is no reason why you should not follow your inner voice.

Extended information:

Steve Jobs’ advice to young people:

Your time is limited, so don’t waste it repeating others in life. Don't be bound by dogma, which means living with the results of other people's thinking. Don’t let the noise of other people’s opinions drown out your true inner voice. And most importantly, you have to have the courage to listen to your intuition and heart - they know on some level what you want to be, and all other things are secondary.

Reference: China Education Network-Jobs: Live every day as if it were your last