2. 18 catechetical words, addressed not to all catechumens, but only to those who are to be baptized on the next Pascha (after the fourth week of Great Lent, an "examination" was held for catechumens, and those who "passed" were admitted "to enlightenment").

3. 5 mystagogic sermons addressed to the newly-baptized. According to the custom of the time, catechumens were not even allowed to be present at the Eucharistic sacrament. They studied the Holy Scriptures, Christian morality and prayers, but they knew nothing about the sacramental life of the Church. Therefore, after baptism, they were given a special explanation of baptism and the Eucharist.

The collection of sermons of St. Cyril is a most valuable source of information about the liturgical life of the Eastern Church in the fourth century. Three more such collections have come down to us - those of St. John Chrysostom and Theodore of Mopsuestia, representing the Antiochian tradition, and the Western Father of the Church, St. Ambrose of Milan. Despite their disunity in space, their content reveals a remarkable similarity of liturgical customs and only minor differences, reflecting the common tradition of the pre-Nicene Church. Here are a few examples.

... When the catechetical teaching is pronounced, if the catechumens inquire of you: "What did the teachers say?" – do not tell anything to the one who stands outside (the Church). For we teach you the mystery and hope of the age to come... Let no one say to you, 'What harm is it if I also know?' And the sick ask for wine; but if it is not given at the right time, it produces insanity of the mind, and there are two bad consequences: the patient dies, and the doctor is slandered. Thus, if the catechumens hear something from the faithful, then the catechumens will fall into madness of mind (for he does not know what he has heard, and condemns the matter, ridicules what has been said), and the faithful is condemned as a traitor. Behold, you are already standing at the very limit; See to it that you do not divulge what is being said, not because it is not worthy of being recounted, but because the ear is not worthy to receive it. And thou wast once a catechumen, and I have not communicated to thee what is now offered. When you eat up the height of what you teach by experience, then you will know that the catechumens are unworthy to hear this.

(Warning Word, par. 12)

This refers to the so-called "discipline of secrecy." Those preparing for enlightenment were told that they were on the threshold of a great mystery. Now they are going to hear very serious things that cannot be talked about with just anyone. The early Church made a strict distinction between dogmatic teaching and preaching (Greek ker'igma). The first concerned the inner, "intimate" life of the Church in the sacraments and was accessible only to the initiated - even catechumens could not be present at the celebration of the sacraments. A sermon or kerygma was a teaching regarding everything else - morality, Holy Scripture, spiritual life, including also a formal doctrine, which is called "dogma" in modern theology. The kerygma was proclaimed outside the Church and was available to everyone.

Интересно, что в наше время это различие совершенно стерлось. Внутренняя жизнь Церкви иногда выставляется напоказ, и совершение таинств можно увидеть даже по телевизору. В некоторых странах, где проповедь христианства запрещена, литургия представляет единственный источник сведений о жизни Церкви. Все, что осталось от раннехристианской «дисциплины секретности», это возглас дьякона «Двери, двери», перед началом литургии верных, открывающейся исповеданием Символа веры. Этот возглас ранее означал, что двери церкви сейчас закроются и что все посторонние должны уйти из собрания посвященных. Теперь этот смысл забыт, и возгласу «Двери, двери» приписывается символически-духовное значение: он толкуется как приглашение открыть двери сердца или души для восприятия веры или же закрыть их для всего остального - в зависимости от вкуса «толкователя».

О смысле таинства крещения св. Кирилл говорит так:

Великое дело - предстоящее крещение, оно - искупление пленным, оставление прегрешений, смерть греха, обновление души, светлое одеяние, святая нерушимая печать, колесница на небо, райское наслаждение, предуготование Царствия, дарование усыновления.

(Там же, пар. 12)