I'm sorry, but I just can't do it.

5 seconds sound clip from the Dark Command (1940) movie soundboard.

You can hear this line at 00:40:32 in the Blu-ray version of the movie.

Quote context

[...]

- You'll have plenty to eat this winter, but what about us? Who's gonna bring in our wheat?

- Where's my husband? I'll tell ya! Murderers!

- Murdered by your fine young snob of a son!

- Look, Bob, we're not in Maryland or Virginia where the laws are so rigid. This is the frontier.

- I have the right to have my son released on bail. Set the amount as high as you like. I'll post it in cash right now.

- I'm sorry, but I just can't do it.

- You bought a horse today from Martin Claussen. The fastest horse he owns.

- Well, that horse could take a man across the border and into safety.

- Would that be so awful?

- He's only a boy.

- He's old enough to carry a gun and use it.

[...]