Now the context: Many dispensalist teach the church lies in a valley, and that the prophets did not see it. They saw from mountain peak to mountain peak. That valley is what the Parenthesis illustration is. The Parenthesis is used to illustrate what Larkin and others taught as the Prophets seeing from messiah coming, being cutoff and then the Kingdom, the church was a valley between the mountains. The valley and peak to peak I was taught but never was a parenthesis church taught. Darby however is not credited with it. The Parenthesis was the teaching mainly of H.A. Ironside. That is what I can find. So the church is normally taught by many dispensationalist as a valley hidden from the prophets, and therefore the mystery spoken of by Paul.