"Self-discipline is often disguised as short-term pain, which often leads to long-term gains. The mistake many of us make is the need and want for short-term gains (immediate gratification), which often leads to long-term pain."
- Charles F. Glassman, Brain Drain The Breakthrough That Will Change Your Life

"Self discipline is that which, next to virtue, truly and essentially raises one man above another."
- Joseph Addison

"I have noticed that sometimes, our success, promotion and accomplishments become real when we say "no" to some things and act the right way. The potential that drives you to do that is called 'self-discipline'."
- Israelmore Ayivor, The Great Hand Book of Quotes 

"Developing willpower and self-discipline can make a great difference in your life, bringing to the fore, inner strength, which is vital for success and for personal growth."
- Remez Sasson, Learn How to Strengthen Your Willpower and Self Discipline
http://www.successconsciousness.com/willpower-self-discipline.html

"Being best at things has nothing to do with talent; it is all about self - discipline and commitment."
- M.F. Moonzajer, Love, Hatred and Madness

"I realized that success is not a one-time act or a moment of luck and that 'Overnight Success' is never true. Success is created through and by creating a habit caused by proper self-discipline."
- Jan Mckingley Hilado, Rich Real Radical: 40 Lessons from a Magna Cum Laude and a College Drop Out

"Without self-discipline, success is impossible, period."
- Lou Holtz

"I have noticed that sometimes, our success, promotion and accomplishments become real when we say ‘no’ to some things and act the right way. The potential that drives you to do that is called 'self-discipline'."
- Israelmore Ayivor, The Great Hand Book of Quotes

"Being best at things has nothing to do with talent; it is all about self - discipline and commitment."
- M.F. Moonzajer, Love, Hatred and Madness