Because the only truth you know is what you get over this tube. Right now, there is a whole and entire generation that never knew anything that didn't come out of this tube.

10 seconds sound clip from the Network (1976) movie soundboard.

You can hear this line at 01:04:10.497 in the Blu-ray version of the movie.

Quote context

[...]

- Edward George Ruddy died today. Edward George Ruddy was the chairman of the board of the Union Broadcasting Systems and he died at 11:00 this morning of a heart condition, and woe is us, we're in a lot of trouble.

- So a rich little man with white hair died. What has that got to do with the price of rice, right? And why is that woe to us?

- Because you people and 62 million other Americans are listening to me right now.

- Because less than 3 percent of you people read books.

- Because less than 15 percent of you read newspapers.

- Because the only truth you know is what you get over this tube. Right now, there is a whole and entire generation that never knew anything that didn't come out of this tube.

- This tube is the Gospel. The ultimate revelation. This tube can make or break presidents, popes, prime ministers!

- This tube is the most awesome goddamn force in the whole godless world! And woe is us if it ever falls into the hands of the wrong people.

- And that's why woe is us that Edward George Ruddy died.

- Because this company is now in the hands of CCA, the Communication Corporation of America.

[...]