I’ve previously shared one of Lacan’s comments from his seminar. Here’s Foucault on the same theme:

Has everyone read these texts? Yes? No? Nobody? Well, I will have to punish you, that’s for sure! I’m not going to tell you how… That’s a surprise for the last day!

Dire vrai sur soi-même: Conférences prononcées à l’Université Victoria de Toronto, 1982, edited by Henri-Paul Fruchaud and Daniele Lorenzini, Paris: Vrin, 2017, p. 189