These quotes discuss hard work and remaining disciplined:
“Discipline is choosing between what you want now and what you want most.” —Augusta F. Kantra
“Plans are only good intentions unless they immediately degenerate into hard work.” —Peter Drucker
“The way to get started is to quit talking and begin doing.” —Walt Disney
“Do not whine. Do not complain. Work harder.” —Joan Didion
“Developing a good work ethic is key. Apply yourself at whatever you do, whether you’re a janitor or taking your first summer job, because that work ethic will be reflected in everything you do in life.” —Tyler Perry
“The future depends on what you do today.” —Mahatma Gandhi
“Work harder than you think you did yesterday.” —Alex Elle
“All growth depends upon activity. There is no development physically or intellectually without effort, and effort means work.” —Calvin Coolidge
“Nothing ever comes to one, that is worth having, except as a result of hard work.” —Booker T. Washington