This quote comes from one of his lectures (I think it was the third one) in the “Gravity and Gladness on Sunday Morning” series, which you can download here.
‘You’ll never hear me on Sunday morning saying, “The problem with this service is people don’t come here to give, they only come to get.” That’s not the problem. You know what the problem is? The problem is people stuff their faces with the white bread of the world and then they come to the banquet table of God’s word and they’re not hungry. And I’m talking television mainly and a lot of other junk that we waste our time on. The world as I look at it is just filled with triviality. . . . Almost all T.V. is trivial. Almost all ads are trivial. They’re silly. It’s an epidemic of silliness, so that the soul that feeds itself on this an hour or two a night . . . can’t help but just shrivel up to the smallest capacities for real, magnificent, glorious joy. . . .
‘How . . . much silly stuff . . . can you watch before you begin to realize you’re a stick-figure, you’re a puppet, you’re just a silly little echo of the silliness coming through that tube continually? . . .’