You probably have read The Screwtape Letters and might remember that, in the 8th letter, Screwtape discusses the Law of Undulation. After some time thinking about it, I do not remember having heard about it or anything similar from any theologian (probably due to my scarce experience reading theology); nevertheless, this ‘law’ strikes me as something real, something which I recognize in my spiritual life. I would very much appreciate if you could tell me anything you know about it regarding theology. Maybe I can accept this law without it having theological background. Thank you for your time.