Matthew Henry on Deuteronomy 29:29

Moses ends his prophecy of the Jews' rejection, just as St. Paul ends his discourse on the same subject, when it began to be fulfilled, Ro 11:33. We are forbidden curiously to inquire into the secret counsels of God, and to determine concerning them. But we are directed and encouraged, diligently to seek into that which God has made known. He has kept back nothing that is profitable for us, but only that of which it is good for us to be ignorant. The end of all Divine revelation is, not to furnish curious subjects of speculation and discourse, but that we may do all the words of this law, and be blessed in our deed. This, the Bible plainly reveals; further than this, man cannot profitably go. By this light he may live and die comfortably, and be happy for ever.