Mystery

the calling of the Gentiles into the Christian Church, so
designated (Eph. 1:9, 10; 3:8-11; Col. 1:25-27); a truth
undiscoverable except by revelation, long hid, now made
manifest. The resurrection of the dead (1 Cor. 15:51), and other
doctrines which need to be explained but which cannot be fully
understood by finite intelligence (Matt. 13:11; Rom. 11:25; 1
Cor. 13:2); the union between Christ and his people symbolized
by the marriage union (Eph. 5:31, 32; compare 6:19); the seven
stars and the seven candlesticks (Rev. 1:20); and the woman
clothed in scarlet (17:7), are also in this sense mysteries. The
anti-Christian power working in his day is called by the apostle
(2 Thess. 2:7) the "mystery of iniquity."