The apostle Paul, throughout his letters, utilizes a very interesting writing style. He knows his local audience and incorporates elements of their society to make theological points. For example, in Corinthians he alludes to special sports competitions that they held. He mentions running and perishable crowns. Near the city of Corinth, the Greeks held the Isthmian games in which people competed in races to obtain a crown of leaves, as noted by Plutarch. Paul uses this aspect of their society to contrast perishable crowns to eternal rewards in heaven.
Likewise, Paul uses the term “Mystery”. In the ancient world, the Mysteries were a series of cults dedicated to various Greek gods. These sacred cults were the religious lifeblood of the Greek world. Each Mystery worshiped a different god (either a Greek god or an imported foreign god) and practiced its own unique celebrations. Initiates into these religious cults were required to undergo a variety of rituals and progress various ranks in order to eventually obtain enlightenment. Enlightenment was the end goal of all good initiates, revealed to the chosen few. The higher level initiates were taught secret teachings, “Mysteries” of which the penalty for revealing was death. Plutarch mentions this facet in his Moralia:
Most of the relevant proofs can lawfully be pronounced or divulged only to those of us who have been initiated into the Perfect Mysteries celebrated every other year, but what I am going to speak of is not forbidden in conversation with friends, especially over after-dinner wine, while we are enjoying god’s own bounty.
Paul latches on to this societal practice and uses it to illustrate his own points. Paul mentions the word “Mystery” over 20 times in six of his letters. Six times it is mentioned to the saints in Ephesus, five times to the saints in Corinthians, and four times to the saints in Colossians. I have written about the Platonism of Colossians previously. Ephesus and Corinth were Mystery Cult hubs.
It is very telling, not only Paul’s interpretation of the Christian mystery, but the way Paul uses the term. As noted before, Mysteries were to be kept secret on the pain of death. Paul, making a mockery of this facet of society, proclaims his Mystery openly. Paul is very specific:
Eph 3:3 how that by revelation He made known to me the mystery (as I have briefly written already…
Eph 3:6 that the Gentiles should be fellow heirs, of the same body, and partakers of His promise in Christ through the gospel,
In Corinthians he openly proclaims a different Mystery:
1Co 15:51 Behold, I tell you a mystery: We shall not all sleep, but we shall all be changed—
1Co 15:52 in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised incorruptible, and we shall be changed.
We see it is not necessarily the noun “Mystery” that is important, but the message behind the word and the cultural understanding of “Mystery”. Paul used the word to denote important theological points that are the lifeblood of Christian theology. To the Ephesians he stressed that the Jews and Gentiles were equal. To the Corinthians he stressed that the dead would rise. He uses the words for a variety of purposes elsewhere (with the Jewish-Gentile equality being the most common usage). Everywhere and always, it indicated a key teaching of Christianity.