We can only ask him

Eustace and Pole, trying to figure out just how they can get to Narnia:

"You mean we might draw a circle on the ground -- and write queer letters in it -- and stand inside it -- and recite charms and spells?"

"Well," said Eustace after he had thought hard for a bit. "I believe that was the sort of thing I was thinking of, though I never did it. But now that it comes to the point, I've an idea that all those circles and things are rather rot. I don't think he'd like them. it would look as if we thought we could make him do things. But really, we can only ask him."

(from C.S. Lewis, The Silver Chair)