Shobogenzo Zuimonki

Book 6

6-14

Dogen instructed,

Students of the Way, when you practice with a certain teacher and learn the dharma, you should listen thoroughly again and again until you completely understand. If you spend time without asking what should be asked, or without saying what should be said, it will certainly be your own loss. Teachers always await questions from their disciples and give their own comments. You should ask again and again to make sure even of things that you have already understood. Teachers also should ask their disciples whether they have really understood or not, and thoroughly convince them (of the truth of the dharma).