Force

The direct use of force is such a poor solution to any problem,
it is generally employed only by small children and large nations.
- David Friedman

Do not attempt to conquer the world with force,
for force only causes resistance.
- Lao Tzu

Don't fight forces, use them.
- R. Buckminster Fuller

Though force can protect in emergency,
only justice, fairness, consideration and cooperation
can finally lead men to the dawn of eternal peace.
- Dwight D. Eisenhower

Force always attracts men of low morality.
- Albert Einstein

Peace cannot be kept by force;
it can only be achieved by understanding.
- Albert Einstein

An invasion of armies can be resisted,
but not an idea whose time has come.
- Victor Hugo

Further reading: The Oak and the Reeds - a fable by Aesop

Use and Misuse of Power

Don't Struggle

Aesop: Gentleness and kind persuasion win where force and bluster fail

Live Softly

The Sailboat Metaphor