That books containing secret lore were kept hidden away by (or for) the "enlightened" is stated in "2 Esdras" xiv. 45-46, where Pseudo-Ezra is told to publish the twenty-four books of the canon openly that the worthy and the unworthy may alike read, but to keep the seventy other books hidden in order to "deliver them only to such as be wise" (compare "Dan". xii. 10); for in them are the spring of understanding, the fountain of wisdom, and the stream of knowledge.