Latin disciplina, "instruction, knowledge"
At its root, discipline signifies training oneself to do something in a controlled and habitual way, whether it be physical skill, social conduct, mental exercise, or spiritual practice.
“The only discipline that lasts is self-discipline.” Zero Dean
“The future depends on what we do in the present.” Mahatma Ghandi
“The first and best victory is to conquer self.” Plato
“Self-discipline equates to self-control. Your ability to control yourself and your actions, control what you say and do, and ensure that your behaviors are consistent with long-term goals and objectives is the mark of a superior person.” Brian Tracy
“Compassion, tolerance, forgiveness and a sense of self-discipline are qualities that help us lead our daily lives with a calm mind.” Dalai Lama
“I could only achieve success in my life through self-discipline, and I applied it until my wish and my will became one.” Nikola Tesla
“Self-discipline begins with the mastery of your thoughts. If you don’t control what you think, you can’t control what you do. Simply, self-discipline enables you to think first and act afterward.” Napoleon Hill
“Self-discipline is a form of freedom. Freedom from laziness and lethargy, freedom from the expectations and demands of others, freedom from weakness and fear – and doubt. Self-discipline allows a person to feel his individuality, his inner strength, his talent. He is the master of, rather than a slave to, his thoughts and emotions.” H. A. Dorfman