In this article the author presents the Church’s teaching on the Holy Trinity, and especially on the Holy Spirit, relying mainly on liturgical texts, where the Church reveals her faith, and on her creeds. On the basis of this the author presents these themes.
1) The dogma of the Holy Trinity is a truth of faith and not a truth resulting from human reason or human experience and experiments.
2) To acknowledge this as a truth of faith is in no way a cause for humiliation or shame for theology, for human reason and understanding by their own nature are limited and incapable in themselves to grasp the fullness of reality. Thus faith is found not only in theology but in science as well as in practical life.
3) Every science and sensible faith is based on someone's positive knowledge. The Christian faith in the Holy Trinity is based on the positive knowledge of Christ. The resurrected Christ, as God, knows that God is the Holy Trinity. Therefore the Christian faith is sensible and reasonable. The Christian knows what he believes, in whom he believes, and why he believes, even when the truth of faith surpasses the possibility of rational understanding as in the case of the dogma of the Holy Trinity.
4) The truthfulness of witness does not rest on the rationality of that which is said but on the credibility of the one who says it. Many scientific truths are clear only to the scientist who has discovered and proven them. Others believe them because of the credibility of the one who witnesses to them. In this respect faith in the Holy Trinity has a far more reliable and credible witness (the Resurrected Christ) than any other purely human science.
5) A mystery is not the same as an absurdity. Absurdity is that which is in pure contradiction with the basic truths of reason, not only human but also divine, in contradiction with clear eternal truths; but a mystery is a truth which surpasses the ability and limits of human reason, which is by its nature limited, but is not in contradiction with it. Accordingly, faith in a mystery, if it is attested to by a credible witness, does not signify a violation of reason. Therefore the criticism of Christian theology that it is by nature against reason is unjustified.
6) The Holy Spirit is the Third Person of the Holy Trinity. He is truly God. He animates existing beings in a number of ways. To lifeless matter he gives the existence which comprises its »life«. He is the source of biological life. He is the source of reason and the knowledge of God. He is the source of prophetic inspiration. He is the source of the spiritual-moral life of isaints, the source of holiness. He is »the Lord, the giver of life«, as stated in the Creed.
7) The activity of the Holy Trinity is always united, for God's essence is one and undivisible. The above-mentioned activity of the Holy Spirit therefore should not be understood as an activity separated from the other two Persons of the Holy Trinity. Rather these activities are signified as the activity of the Holy Spirit because in them we see the activity of the Holy Spirit more evidently than the activity of the other two Persons, although they are implied. This was intended to stress the true divine equality and consubstantiality of the Holy Spirit with the Father and the Son.
8) The regular means of the action of the Holy Spirit is through the Holy Mysteries (Sacraments). He, however, is God and therefore is not limited in His activity by anything, not even by the Sacraments. Consequently, he can act, and in fact does act, outside of the Sacraments when He considers it necessary. In this manner He acted through the prophets and through the Holy Theotokos before the Sacraments were instituted.
9) The personal characteristic of the Holy Spirit is that he eternally proceeds from the Father. That is the only truth about Him to which Christ witnesses. Other additions, as for example the filioque, even if they would be logically justified, would be superfluous, for no man can add anything to Christ's knowledge of the Holy Trinity in general and on the Holy Spirit in particular.