A definition Neville repeats across some twenty-seven lectures and uses to clear away the idea of an initiate's secret. A mystery is not something to be kept as a secret, but a truth that is mysterious in character - so nothing is being withheld from anyone, and the difficulty is in the thing itself and not in the telling. The consequence he draws is about method: the Bible is not like any other book in the world because it is God's history and a mystery in that sense, and the way it is unravelled is not by study but by happening - in my own case it happened, the whole thing unfolded in me, and I am sharing my own experience. That is also why he can tell everything he knows from a public platform without feeling that he is giving anything away: telling a mystery does not dissolve it, and the hearer who has not had it still has to have it.