I am of course referring to patriotic spies... not mercenaries.

6 seconds sound clip from the The 39 Steps (1937) classic radio play.

You can hear this line at 00:39:49 in the radio play.

Quote context

[...]

- In addition, he must have common sense, a good general education, an ability to take orders and preferably a knowledge of foreign languages.

- I've noticed that the opinion held of a spy varies greatly.

- Some people have only the greatest respect and admiration for a spy, others consider them vicious, double-dealing scoundrels who stop at nothing to attain their ends.

- How well do I know that.

- But I think these people would change their minds if they only realized that spies are one of the greatest forces for world peace.

- I am of course referring to patriotic spies... not mercenaries.

- I believe that a patriotic spy, by keeping his country informed of military activity in other lands, enables his own nation to properly prepare itself...

- And a properly prepared nation is a nation seldom attacked. The war that they are ready for rarely comes.

- If what I've observed is true, you soldiers who fight with your brains instead of bayonets are finding more and more women as your co-workers.

- How does a woman compare with a man as a spy?

- Very favorably... up to one point.

[...]