Light Side:

Peace over Anger.
Honor over Hate.
Strength over Fear.
-Jedi Motto

There is no emotion; there is peace.
There is no ignorance; there is knowledge.
There is no passion; there is serenity.
There is no death; there is the Force.
A Jedi does not act for personal power or wealth, but seeks knowledge and enlightenment.
A True Jedi never acts from hatred, anger, fear, or aggression, but acts when calm and at peace with the Force.
-The Jedi Code

Concentrate on the moment; feel, don't think; use your instincts.
-Qui-Gon Jinn

Jedi are not saints, but seekers
-Jedi Saying

Doubt in battle,there cannot be.
Belief, there must be.
Belief, in the Force.
Reach for it, you will.
-Master Yoda

Always more questions than answers, there are.
-Master Yoda

Learn to lose as well as win, a Jedi must
-Master Yoda

To defeat an enemy, you do not have to kill.
Defeat the rage that burns in him, and he is your enemy no longer.
Rage the true enemy is.
-Master Yoda

When the path is unsure, better to wait, it is
-Master Yoda

Dark Side:

Disruption + Demoralization + Distraction = Devastation
-Xanatos

We are the power in the galaxy
We are the defenders of order
We are the destruction of everything good
We are the killers of worlds
We are everywhere
We are the Dark Side
-The Sith Code