Why? They asked you to do something that made you feel dishonest, didn't they? They asked you to spy on me, didn't they?
15 seconds sound clip from the Star Wars: Episode III - Revenge of the Sith movie soundboard.
You can hear this line at 00:44:55 in the Blu-ray version of the movie.
Quote context
[...]
- The Jedi Council want control of the Republic. They're planing to betray me.
- Anakin. Search your feelings. You know? Don't you?
- I know they don't trust you.
- Hmm. Or the senate. Or the Republic. Or democracy, for that matter.
- I have to admit my trust in them has been shaken.
- I don't, uh I don't know what to say.
- Remember back to your early teachings. All who gain power are afraid to lose it. Even the Jedi.
- The Jedi use their power for good.
- Good is a point of view, Anakin.
- The Sith and the Jedi are similar in almost every way, including their quest for greater power.
[...]