'Mystery' in the Bible

Daniel was seeking mercy, in order to ask about this mystery in the presence of the God of heaven, so that Daniel and his friends might not be executed along with the rest of the advisors of Babylon.

When the mystery was revealed to Daniel in a vision later that night, Daniel blessed the God of heaven

The king told Daniel, "Truly your God is the God of gods, the Lord of kings, and the Revealer of Secrets, because you were able to reveal this mystery."

"Belteshazzar, chief of the diviners, since I know that the spirit of the holy gods is within you, and no mystery too difficult for you, explain to me the vision of my dream that I saw, along with its interpretation.