Pentecost has also been a time when traditionally the church has emphasized and defended the doctrine of the Trinity and the coequal place of the Spirit in it. The icon of the Holy Trinity comes to the forefront of Orthodox worship and Roman Catholics are encouraged to say the novena to the Holy Spirit. The prayers are quite beautiful and they stress the real place of the Spirit as part of the divine Godhead:
" Come, O blessed Spirit of Holy Fear, penetrate my inmost heart, that I may set Thee, my Lord and God, before my face forever; help me to shun all things that can offend Thee, and make me worthy to appear before the pure eyes of Thy Divine Majesty in heaven, where Thou livest and reignest in the unity of the ever Blessed Trinity, God world without end. Amen
Gregory Naziansus, in the fourth century, articulated and defended the divinity of the Holy Spirit with such acuity and vigor that he earned himself the epithet "the Theologian." It is unsurprising that his oration on the occasion of Pentecost in 381 is a vehicle for expressing this doctrine. In Constantinople, where the sermon was preached, what would be the second ecumenical council was in session. Gregory and his thought on the Spirit would be instrumental in its final decision which is properly lauded as the definitive victory for the doctrine of the Trinity in Christianity. The following selection from this oration is intended to be more inspirational than doctrinal, but it is important to remember that these truths about the Spirit that are taken for granted or neglected in modern Christianity were under constant assault in Gregory's day. What he preached was the profound mystery of the Godhead against all foreign and dangerous doctrine which would strip the Christian religion of perhaps its most foundational and normative doctrine.
Gregory the Theologian, "On Pentecost,"
Honour the Day of the Spirit; restrain your tongue if you can a little. It is the time to speak of other tongues—reverence them or fear them, when you see that they are of fire...He wrought first in the heavenly and angelic powers, and such as are first after God and around God. For from no other source flows their perfection and their brightness, and the difficulty or impossibility of moving them to sin, but from the Holy Ghost. And next, in the Patriarchs and Prophets, of whom the former saw Visions of God, or knew Him, and the latter also foreknew the future, having their master part moulded by the Spirit, and being associated with events that were yet future as if present, for such is the power of the Spirit. And next in the Disciples of Christ (for I omit to mention Christ Himself, in Whom He dwelt, not as energizing, but as accompanying His Equal), and that in three ways, as they were able to receive Him, and on three occasions; before Christ was glorified by the Passion, and after He was glorified by the Resurrection; and after His Ascension, or Restoration, or whatever we ought to call it, to Heaven. Now the first of these manifests Him—the healing of the sick and casting out of evil spirits, which could not be apart from the Spirit; and so does that breathing upon them after the Resurrection, which was clearly a divine inspiration; and so too the present distribution of the fiery tongues, which we are now commemorating. But the first manifested Him indistinctly, the second more expressly, this present one more perfectly, since He is no longer present only in energy, but as we may say, substantially, associating with us, and dwelling in us. For it was fitting that as the Son had lived with us in bodily form—so the Spirit too should appear in bodily form; and that after Christ had returned to His own place, He should have come down to us—Coming because He is the Lord; Sent, because He is not a rival God. For such words no less manifest the Unanimity than they mark the separate Individuality...
But as the old Confusion of tongues was laudable, when men who were of one language in wickedness and impiety, even as some now venture to be, were building the Tower; for by the confusion of their language the unity of their intention was broken up, and their undertaking destroyed; so much more worthy of praise is the present miraculous one. For being poured from One Spirit upon many men, it brings them again into harmony.