- He knows everything.
- He'll know too much for his own good someday.

6 seconds sound clip from the The Big Trail (1930) movie soundboard.

You can hear this line at 00:16:04 in the Blu-ray version of the movie.

Quote context

[...]

- Who's that young buck over there with no hair on his face?

- That's, uh, Breck Coleman. He very quick with his knife.

- Oh, where's he come from?

- He come from the plains, the mountains. He live with the Indians.

- He can throw a knife through the heart in 20 feet. He's the best shot in all this country.

- He knows everything.

- He'll know too much for his own good someday.

- Yes. All right.

- If old Ben had lived, he'd be going on about 72 now, wouldn't he?

- Injuns never done this. It was renegade whites.

- And they've left their mark.

[...]