Work on yourself more than you do on your job.

Jim Rohn

Work eight hours and sleep eight hours and make sure that they are not the same hours.

T. Boone Pickens

If you want to be one of the few to defy those trends in our ever-softening society, you will have to be willing to go to war with yourself and create a whole new identity, which requires an open mind.

David Goggins

With self-discipline most anything is possible.

Theodore Roosevelt

Willpower isn't just a skill. It's a muscle, like the muscles in your arms or legs, and it gets tired as it works harder, so there's less power left over for other things.

Charles Duhigg

He who overcomes himself is mighty.

Lao Tzu