“A mystery is a truth that cannot be known except through divine revelation—a sacred secret. In the days of Paul the important truth that Gentiles were to be admitted to the Kingdom of God without observing the Law of Moses was a ‘mystery’ (Eph. 1:9–11; Col. 1:25–27). In our day such great truths as those pertaining to the restoration of the Priesthood, the work for the dead, and the re-establishment of the Church are ‘mysteries,’ because they could not have been discovered except by revelation” (Smith and Sjodahl, Doctrine and Covenants Commentary, 141).