Before passing on to the teaching of the Cappadocian Fathers, who finally resolved the dispute about the Holy Trinity, it is necessary to dwell on the remarkable personality of St. Cyril of Jerusalem (c.315-387). His life and teaching reflected all the troubles and problems of church life in the middle of the fourth century and can give us a clear idea of the spirit of that era.

St. Cyril was ordained a presbyter in the year 349, and already in the year 350 he was elected bishop of Jerusalem. The Church was then experiencing serious difficulties caused by the Arian turmoil. Until 337, the empire was ruled by Constantine I, who at the end of his life patronized the Arians and removed most of the Orthodox bishops from their sees. In 336, Arius himself was allowed to return from exile, and he would have been received back into the fold of the Church, had it not been for his sudden death.

What place in all this belongs to Cyril of Jerusalem? - Many theologians of antiquity and subsequent times ranked him among the Arians on the grounds that he had received consecration as bishop from the Arian Acacius of Caesarea. Such an argument is not entirely justified: after all, the undoubtedly Orthodox saint, Basil the Great, was ordained in 370, when in the East the Orthodox Nicene definition of faith was still rejected by almost everyone. In the Second Ecumenical Council, Cyril of Jerusalem participated on the Orthodox side, and his way of thinking is also in full accord with the Orthodox faith. In general, in assessing the ecclesiastical situation in the fourth century, extreme judgments should be avoided. It can be shown by examples that the majority of the Eastern bishops, although they did not fully recognize the Nicene definition of the faith, at the same time did not agree with the Arian heresy. They were repelled from the Nicene Creed only by the word "consubstantial," which, according to their concepts, aroused suspicion of modalism. But no one was satisfied with the doctrine of subordination in the Holy Trinity, which directly followed from the Arian ideas. Most of the clergy vacillated somewhere between modalism and subordinationism, and in fact had an almost Orthodox way of thinking, which can be defined as "not quite Nicene Orthodoxy": they were Orthodox in thought, but not in formal confession of faith. Unfortunately, in the theology of that time there was no terminology suitable for the exact expression of the opinions held by the majority. At that time, the word "similar" or "similar" (omiousios) came into use. Following Origen, most Syrian and Palestinian theologians believed that Christ was the "likeness" of God, that their essences were "similar." The situation was very confusing, and it was up to the Cappadocian theologians, who came from among the supporters of "subservience" and understood all sides of the problem well, to unravel it.

It was at this time that Cyril became bishop of Jerusalem. His position was very difficult from the very beginning. Initiated to the rank by the convinced Arian Akakios, he at the same time supported St. Athanasius when he was hiding from persecution against the Orthodox. Cyril was three times deposed by the Arians from the episcopal cathedra and three times reinstated, but nevertheless, when in 381 the Second Ecumenical Council in Constantinople restored Orthodoxy, some doubted the Orthodoxy of his views. In 382, a council was convened, at which this issue was especially discussed. The Council sent a letter to the Pope of Rome, in which it was reported that Bishop Cyril "struggled against the Arians" and had an Orthodox way of thinking.

Of the works of St. Cyril, the collection of his sermons to the catechumens in three parts is especially known:

1. Prokatechizis - "preliminary" catechetical sermons, something like an introductory course for those preparing for baptism.

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)