'Secret' in the Bible

"None of the advisors, enchanters, diviners, or astrologers can explain the secret that the king has requested to be made known. But there is a God in heaven who reveals secrets, and he is making known to King Nebuchadnezzar what will happen in the latter days.

As for me, this secret was made known to me, not because my own wisdom is greater than anyone else alive, but in order that the meaning may be made known to the king, and that you might understand the thoughts of your heart.

The vision about the twilights and dawnings that has been related is trustworthy, but keep its vision secret, because it pertains to the distant future.'