'Mysteries' in the Bible

"He uncovers mysteries out of darkness, and he brings deep shadow to the light.

But there is a God in heaven [who] reveals mysteries, and he has made known to King Nebuchadnezzar what [it is] that will be at the end of days. This [is] your dream and the visions of your head on your bed.

"[As for you], king, your thoughts on your bed {turned to} what [it was] that would be {in the future}, and the revealer of mysteries has made known to you what that would be.

The king answered Daniel and said, "{Truly} your God [is] the God of gods and the Lord of kings, and he reveals mysteries, for you are able to reveal this mystery."