The New Testament seeks to clarify, not to mystify, the gospel!
Are not predestination and authentic human freedom of choice both part of “the mystery of the gospel” and integral components of God’s redemptive plan?
Since the Bible nowhere presents predestination as something that continues to be mysterious and hidden, what would now be the point of mystifying this basic truth of the gospel?
In these references the recurrent phrase, “make known the mystery of the gospel.”
Paul never attempted to relegate predestination, election, choice, or free will to the realm of hidden things. Nevertheless, Calvin maintained that God not only had a “revealed” will, but also a “secret” will, which was different from, and could even contradict, His declared will.
Let me assure you straight up that God does not have a second, secret will that acts independently of, and can be at variance with, His revealed will. Paul knew that we could always trust our heavenly Father to be totally straight and up-front with His children.