Below are a few selected quotes that reinforce the importance of execution:

“Setting a goal is not the main thing. It is deciding how you will go about achieving it and staying with the plan.”
Tom Landry

“85% of people believe they are in the top 25% of their peer group. Which means that 60% of your employees are delusional about their performance.”
Marshall Goldsmith

“If the minimum wasn’t good enough it wouldn’t be the minimum”
Anonymous Army guy

“Managers love complexity. Complexity is stimulating and intellectually challenging... But complexity is also sponsored by managers, just as it sponsors them. Most organizations are conspiracies of management against the interests of customers and investors.”
Richard Koch

“The reasonable man adapts himself to the world. The unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.”-
George Bernard Shaw

“Strategy equals Execution. All the great ideas and visions in the world are worthless if they can't be implemented rapidly and efficiently.”-
Colin Powell

“Most people want to tell you how difficult life is so they can fail with dignity.
Anonymous

“Don’t confuse activity with achievement.”–
John Wooden

“If you cannot explain it simply, you do not understand it well enough".–
Albert Einstein

“However beautiful the strategy, you should occasionally look at the results.”
Winston Churchill

“Some of us will do our jobs well, and some will not, but we will be judged by only one thing.
The result.”
Vince Lombardi

“Speech is conveniently located midway between thought and action, where it often substitutes
for both.”
John Andrew Holmes

“Action, this day.”
Winston Churchill