A MYSTERY — but emphatically not a puzzle or something unknowable. In Paul it is an OPEN SECRET: something long hidden in God and now announced, whose content he states plainly at Ephesians 3:6 — that Gentiles are fellow heirs, in the same body. ⚠ This is nearly the opposite of the word's use in the Hellenistic MYSTERY-RELIGIONS, where a mystērion was what initiates must never reveal; Paul's mysteries are precisely the things now published. The Latin Vulgate sometimes rendered it sacramentum, which is how 'mystery' and 'sacrament' came to be entangled in Western theology. → first discussed at Ephesians 1:9