The evidence is strong that the Mysteries had a real spiritualising and moralising influence on large numbers of those who were initiated, and that this influence was increasing under the early empire.  The ceremonies may have been trivial, and even at times ludicrous; but the discovery had been made that the performance of solemn acts of devotion in common, after ascetical preparation, and with the aid of an impressive ritual, is one of the strongest incentives to piety.  Diodorus is not alone in saying (he is speaking of the Samothracian Mysteries) that “those who have taken part in them are said to become more pious, more upright, and in every way better than their former selves.”

The chief motive force which led to the increased importance of Mystery-religion in the first centuries of our era, was the desire for “salvation” ([Greek:  soteria]), which both with pagans and Christians was very closely connected with the hope of everlasting life.  Happiness after death was the great promise held out in the Mysteries.  The initiated were secure of blessedness in the next world, while the uninitiated must expect “to lie in darkness and mire after their death” (cf.  Plato, Phaedrus, 69).

How was this “salvation” attained or conferred?  We find that several conflicting views were held, which it is impossible to keep rigidly separate, since the human mind at one time inclines to one of them, at another time to another.

(a) Salvation is imparted by revelation.  This makes it to depend upon knowledge; but this knowledge was in the Mysteries conveyed by the spectacle or drama, not by any intellectual process.  Plutarch (de Defect.  Orac. 22) says that those who had been initiated could produce no demonstration or proof of the beliefs which they had acquired.  And Synesius quotes Aristotle as saying that the initiated do not learn anything, but rather receive impressions ([Greek:  ou mathein ti dein alla pathein]).  The old notion that monotheism was taught as a secret dogma rests on no evidence, and is very unlikely.  There was a good deal of [Greek:  theokrasia], as the ancients called it, and some departures from the current theogonies, but such doctrine as there was, was much nearer to pantheism than to monotheism.  Certain truths about nature and the facts of life were communicated in the “greatest mysteries,” according to Clement, and Cicero says the same thing.  And sometimes the [Greek:  gnosis soterias] includes knowledge about the whence and whither of man ([Greek:  tines esmen kai ti gegonamen], Clem. Exc. ex Theod. 78).  Some of the mystical formulae were no doubt susceptible of deep and edifying interpretations, especially in the direction of an elevated nature-worship.