I speak not to disprove what Brutus spoke, but here I am to speak what I do know.
9 seconds sound clip from the Julius Caesar (1953) movie soundboard.
You can hear this line at 01:14:04 in the DVD version of the movie.
Quote context
[...]
- Ambition should be made of sterner stuff.
- Yet Brutus says he was ambitious, and Brutus is an honorable man.
- Yet Brutus says he was ambitious, and, sure, he is an honorable man.
- I speak not to disprove what Brutus spoke, but here I am to speak what I do know.
- You all did love him once, not without cause.
- What cause withholds you then to mourn for him?
- O judgment! Thou art fled to brutish beasts, and men have lost their reason!
- Bear with me. My heart is in the coffin there with Caesar, and I must pause till it come back to me.
[...]