'Mystery' in the Bible

the mystery which has been hidden for ages and generations. But now it has been revealed to his saints,

to whom God was pleased to make known what are the riches of the glory of this mystery among the Gentiles, which is Christ in you, the hope of glory;

that their hearts may be comforted, they being knit together in love, and gaining all riches of the full assurance of understanding, that they may know the mystery of God, both of the Father and of Christ,

praying together for us also, that God may open to us a door for the word, to speak the mystery of Christ, for which I am also in bonds;