Real mystery is the real Word of God

Roman Catholic apologist Dave Armstrong's 14th reason why he is a Roman Catholic:

14. Catholicism retains (to the fullest extent) the elements of mystery, supernatural, and the sacred in Christianity, thus opposing itself to secularization, where the sphere of the religious in life becomes greatly limited.

Teenage girls who wear alot of black think their bedrooms become more "mysterious", "supernatural", and "sacred" if they turn off the lights and light a candle...

The Doctrines of Grace are high mystery (and difficult if not nigh impossible for vanity, worldly pride, and self-will to accept, let alone see). Covenant Theology elucidates the deep mystery of God's plan of redemption and the history of redemption from before time, in the council of the Godhead in eternity, to when time is no more. Calvinism - Reformed Theology - because it values the Word of God as authority, recognizes where the Bible leaves off individual doctrine at the ceiling of mystery and accepts it.