Because you have been down there, Neo.
4 seconds sound clip from the The Matrix movie soundboard.
You can hear this line at 00:23:37 in the Blu-ray version of the movie.
Quote context
[...]
- Listen to me, coppertop. We don't have time for 20 Questions.
- Right now, there's only one rule: Our way... or the highway.
- Fine.
- Please, Neo, you have to trust me.
- Why?
- Because you have been down there, Neo.
- You know that road. You know exactly where it ends. And I know that's not where you want to be.
- Lie back. Lift up your shirt.
[...]