St. Basil, the Great Bishop of Cæsarea, born in the year 326, and dying in the year 376, says: "We receive the dogmas transmitted to us by writing, and those which have descended to us from the Apostles, beneath the mystery of oral tradition: for several things have been handed to us without writing, lest the vulgar, too familiar with our dogmas, should lose a due respect for them. … This is what the uninitiated are not permitted to contemplate; and how should it ever be proper to write and circulate among the people an account of them?"
St. Gregory Nazianzen, Bishop of Constantinople, A.D. 379, says; "You have heard as much of the Mystery as we are allowed to speak openly in the ears of all; the rest will be communicated to you in private; and that you must retain within yourself…. Our Mysteries are not to be made known to strangers."
St Ambrose, Archbishop of Milan, who was born in 340, and died in 393, says in his work De Mysteries: "All the Mystery should be kept concealed, guarded by faithful silence, lest it should be inconsiderately divulged to the ears of the Profane….. It is not given to all to contemplate the depths of our Mysteries….. that they may not be seen by those who ought not to behold them; nor received by those who cannot preserve them." And in another work: "He sins against God, who divulges to the unworthy the Mysteries confided to him. The danger is not merely in violating truth, but in telling truth, if he allow himself to give hints of them to those from whom they ought to be concealed…..Beware of casting pearls before swine!… Every Mystery ought to be kept secret; as it were, to be covered over by silence, lest it should rashly be divulged to the ears of the Profane. Take heed that you do not incautiously reveal the Mysteries!"
St. Augustine, Bishop of Hippo, who was born in 347, and died in 430, says in one of his discourses: "Having dismissed the Catechumens, we have retained you only to be our hearers; because besides those things which belong to all Christians in common, we are now to discourse to you of sublime Mysteries, which none are qualified to hear, but those who, by the Master's favor, are made partakers of them…..To have taught them openly, would have been to betray them." And he refers to the Ark of the Covenant and says that it signified a Mystery, or secret of God, shadowed over by the cherubim of glory, and honored by being veiled.
St. Chrysostom and St. Augustine speak of initiation more than fifty times. St. Ambrose writes to those who are initiated; and initiation was not merely baptism, or admission into the church, but it referred to initiation into the Mysteries. To the baptized and initiated the Mysteries of religion were unveiled; they were kept secret from the Catechumens; who were permitted to hear the Scriptures read and the ordinary discourses delivered, in which the Mysteries, reserved for the Faithful, were never treated of. When the services and prayers were ended, the Catechumens and spectators all withdrew.
Chrysostom, Bishop of Constantinople, was born in 354, and died in 417. He says: "I wish to speak openly: but I dare not, on account of those who are not initiated. I shall therefore avail myself of disguised terms, discoursing in a shadowy manner….. Where the holy Mysteries are celebrated, we drive away all uninitiated persons, and then close the doors" He mentions the acclamations of the initiated; "which", he says, "I here pass over in silence; for it is forbidden to disclose such things to the Profane". Palladius, in his life of Chrysostom, records, as a great outrage, that, a tumult having been excited against him by his enemies, they forced their way into the penetralia, where the uninitiated beheld what was not proper for them to see; and Chrysostom mentions the same circumstance in his epistle to Pope Innocent.
St. Cyril of Alexandria, who was made Bishop in 412, and died in 444, says in his 7th Book against Julian: "These Mysteries are so profound and so exalted, that they can be comprehended by those only who are enlightened. I shall not, therefore, attempt to speak of what is so admirable in them, lest by discovering them to the uninitiated, I should offend against the injunction not to give what is holy to the impure, nor cast pearls before such as cannot estimate their worth…..I should say much more, if I were not afraid of being heard by those who are uninitiated: because men are apt to deride what they do not understand. And the ignorant, not being aware of the weakness of their minds, condemn what they ought most to venerate."
Theodoret, Bishop of Cyropolis in Syria, was born in 393, and made Bishop in 420. In one of his three Dialogues, called the Immutable, he introduces Orthodoxus, speaking thus: "Answer me, if you please, in mystical or obscure terms: for perhaps there are some persons present who are not initiated into the Mysteries." And in his preface to Ezekiel, tracing up the secret discipline to the commencement of the Christian era, he says: "These Mysteries are so august, that we ought to keep them with the greatest caution."
Minucius Felix, an eminent lawyer of Rome, who lived in 212, and wrote a defence of Christianity, says: "Many of them [the Christians] know each other by tokens and signs (notis et insignibus), and they form a friendship for each other, almost before they become acquainted."
The Latin Word, tessera, originally meant a square piece of wood or stone, used in making tesselated pavements; afterward a tablet on which anything was written, and then a cube or die. Its most general use was to designate a piece of metal or wood, square in shape, on which the watchword of an Army was inscribed; whence tessera came to mean the watchword itself. There was also a tessera hospitalis, which was a piece of wood cut into two parts, as a pledge of friendship. Each party kept one of the parts; and they swore mutual fidelity by Jupiter. To break the tessera was considered a dissolution of the friendship. The early Christians used it as a Mark, the watchword of friendship. With them it was generally in the shape of a fish, and made of bone. On its face was inscribed the word [Greek: Ίχθύς], a fish, the initials of which represented the Greek words, [Greek: Ιησούς Χριστός ϴεού Υίός Σωτήρ]; Jesus Christ, the Son of God, the Saviour.