Whether you’re in the early stages of your startup or you’ve been running your own business for a while, being an entrepreneur takes guts. The road to success can be grueling, frustrating, and exhausting. However, it also provides deep rewards that are only earned by those who are willing to take big chances, pursue their passions and turn their dreams into reality.

On the days that you’d rather throw in the towel instead of push ahead, don’t forget that other entrepreneurs throughout history have shared your same struggles. That’s when a perfect quote from someone who has overcome the obstacles can be just what you need to turn it all around. Here’s a short compilation of quotes from successful entrepreneurs whose insights can inspire you on your journey.

1. “Don’t let what you don’t know scare you, because it can become your greatest asset. And if you do things without knowing how they have always been done, you’re guaranteed to do them differently.” Sara Blakely, Spanx

2. “I want to work for a company that contributes to and is part of the community. I want something not just to invest in. I want something to believe in.” Anita Roddick, The Body Shop

3. “Failure is an option here. If things are not failing, you are not innovating enough.” Elon Musk

4. “If you’ve got an idea, start today. There’s no better time than now to get going. That doesn’t mean quit your job and jump into your idea 100 percent from day one, but there’s always small progress that can be made to start the movement.” Kevin Systrom, Instagram

5. “For all of the most important things, the timing always sucks. Waiting for a good time to quit your job? The stars will never align and the traffic lights of life will never all be green at the same time. The universe doesn’t conspire against you, but it doesn’t go out of its way to line up the pins either. Conditions are never perfect. “Someday” is a disease that will take your dreams to the grave with you. Pro and con lists are just as bad. If it’s important to you and you want to do it “eventually,” just do it and correct course along the way.” Timothy Ferriss, author of The 4-Hour Work Week

6. “The biggest risk is not taking any risk. In a world that’s changing really quickly, the only strategy that is guaranteed to fail is not taking risks.” Mark Zuckerberg

7. “I’m convinced that about half of what separates the successful entrepreneurs from the non-successful ones is pure perseverance.” Steve Jobs 

8. “You have to be willing to be misunderstood if you’re going to innovate.” Jeff Bezos

9. “My biggest motivation? Just to keep challenging myself. I see life almost like one long university education that I never had — every day I’m learning something new.” Richard Branson

10. “I just love bossy women. I could be around them all day. To me, bossy is not a pejorative term at all. It means somebody’s passionate and engaged and ambitious and doesn’t mind leading.” Amy Poehler, actress

11. “The critical ingredient is getting off your butt and doing something. It’s as simple as that. A lot of people have ideas, but there are few who decide to do something about them now. Not tomorrow. Not next week. But today. The true entrepreneur is a doer, not a dreamer.” Nolan Bushnell, Atari, Inc.

12. “When everything seems to be going against you, remember that the airplane takes off against the wind, not with it.” Henry Ford, Ford Motor Company

13. “It’s almost always harder to raise capital than you thought it would be, and it always takes longer. So plan for that.” Richard Harroch, venture capitalist

14. “The media wants overnight successes (so they have someone to tear down). Ignore them. Ignore the early adopter critics that never have enough to play with. Ignore your investors that want proven tactics and predictable instant results. Listen instead to your real customers, to your vision and make something for the long haul. Because that’s how long it’s going to take, guys. Seth Godin, entrepreneur

15. “Timing, perseverance, and ten years of trying will eventually make you look like an overnight success.” Biz Stone, co-founder of Twitter