Here are several.

Laws do not persuade just because they threaten.
— Seneca, A.D. 65

 Two of the gravest general dangers to survival are the desire for comfort and a passive outlook.
— U.S. Army Ranger Handbook

 I do not believe in the collective wisdom of individual ignorance.
— Thomas Carlyle

 We can never solve our significant problems from the same level of thinking we were at when we created the problems.
— Albert Einstein

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

 “Political necessities sometime turn out to be political mistakes.” George Bernard Shaw

 ”Wise men talk because they have something to say; fools, because they have to say something.” Plato

 “All government, indeed every human benefit and enjoyment, every virtue, and every prudent act, is founded on compromise and barter.” Edmund Burke

 “Well done is better than well said.” Benjamin Franklin

 “You must be the change you wish to see in the world.” Mahatma Gandhi

“We cannot solve today’s problems using the mindset that created them.” Albert Einstein

 “Do not go where the path may lead, go instead where there is no path and leave a trail.” Ralph Waldo Emerson

“The highest reward for a man’s toil is not what he gets for it but what he becomes by it.” John Ruskin