In the ancient days a sacrament was simply a holy thing, something consecrated and set apart; in very early times it was especially a sort of judicial pledge deposited by the parties in a law [p.59] suit; then it came to mean the solemn oath of a soldier, pledging his loyalty to his commander on entering upon his military service. It was used by early Christian Latin writers to render the thought of the Greek mystery, /μυστήριον/, a word which we have failed to translate into English, as so often we must fail in any translation from one tongue to another to render thought for thought. We think nowadays of a mystery as being something hidden, but to the Greek it was rather a revelation; an unfolding through symbol of that which could not be wholly expressed in any words. The mystery remained a secret to him who was without, to the uninitiate; but the initiate understood its meaning. In the most famous mysteries of Greece, those which were celebrated at Eleusis, it would seem that along with the idea of revelation of truth went also the sense of upbuilding of the inward life, the purification of the soul and the assimilation of the Divine things imparted beneath the symbol. For revelation, the unveiling of truth, is no one-sided act; it involves response in the mind that receives; if the truth is apprehended, it must in part at least, be also assimilated. And so every mystery is something more than the unfolding of a hidden reality; it also implies the imparting of new life.[7] [p.60 ] In the earlier Christian literature sacraments still bear this wide meaning. Tertullian often uses the word thus. In one passage he speaks of a woman known to him who was accustomed to go into ecstasies during the weekly service of the Church; "she converses with angels, sometimes even with the Lord, and both sees and hears sacraments" [8] He speaks of "the sacrament of allegory,"[9] "sacraments of metaphors," [10] in both cases alluding to Old Testament types, and again, he explains the wood by which Moses made the waters of Mara sweet (Exodus xv.), as a sacrament symbolizing the cross [11] <#_edn11> According to Prudentius, the early Christian poet, the Evangelist tells us that Christ gave these [p.61] commands to His disciples: "Seek not carefully for words when ye shall have to descant of my sacrament," [12] "my Sacrament," being evidently here equivalent to "the Gospel." But, as time passed by, the word sacrament became more and more used for certain mysteries of the Church alone, although far down into the middle ages even in this sense the word had a wider use than that of the seven sacraments of the Council of Trent.