Exposition of Trinitarian Faith by St. Gregory of Nazianzus (ca 329 - 390 AD)

(Gregory of Nazianzus (ca 329 - 390 AD) was Archbishop of Constantinople who presided over Ecumenical Council of Constantinople in 381 AD. He was one of the main architects involved in expansion of the clause concerning Holy Spirit in the Niceno-Constantinopolitan Creed. He was one of the major defenders of Trinitarian theology through his famous theological orations and is rightly called Gregory the Theologian. He is considered one of the Cappadocian fathers (along with Basil of Caesarea and Gregory of Nyssa). This is taken from his Theological Oration 25 given in honor of Maximus I of Constantinople, where he clearly explicates Trinitarian faith)

Define our faith by teaching the knowledge of One God, Unbegotten, the Father; and One Begotten Lord, His Son; and One Holy Spirit, who proceeds or goes forth from the Father, to those who understand things properly—combated by the impious but understood by those who are above them, and even professed by those who are more spiritual;

Teach that we must not make the Father subject to another source, lest we posit a ‘‘first of the First,’’ and thus overturn the divine existence; nor should we say that the Son or the Holy Spirit is without source, lest we take away the Father’s special characteristic. For they are not without source—and yet in a sense they are without source, which is a paradox. They are not without source with respect to their cause, for they are from God even if they are not subsequent to him in time, just as light comes from the sun. But they are without source with respect to time, since they are not subject to time. And teach that we do not believe in three first principles, lest we espouse the polytheism of the Greeks; nor in a solitary principle, Jewish in its narrowness and somewhat grudging and ineffectual, either by positing a self-absorbing Deity or by casting down the natures of the Son and Spirit and making them foreign to Divinity—as though Divinity feared some rival opposition, or was able to produce nothing higher than creatures!

Teach that the Son is not unbegotten, for the Father is unique; and that the Spirit is not Son, for the Only-Begotten is unique, the result being that they each possess this divine quality of uniqueness, the one sonship and the other procession, which is different from sonship. Rather, teach that the Father is truly a father—much more truly even than human fathers are—because He is a Father uniquely and distinctively, in a way different from corporeal beings; unique, being without a mate; of one who is unique, namely the Only-Begotten; He is only a Father, since He was not formerly a Son; completely a Father and father of One who is complete; and Father from the beginning, since He did not become a Father at a later point in time. Teach that the Son is truly a son, because he is Son alone, of One alone, absolutely, and only, since He is completely a Son, and of One who is complete, and from the beginning, having never come to be a Son, since His Divinity is not due to a change of purpose, nor His divinization to moral progress, otherwise there would be a time when the One was not a Father and the Other was not a Son.

Teach that the Holy Spirit is truly holy, because there is nothing else that is like it or holy in the same way. Its sanctification does not come by way of addition, but it is holiness itself, It is neither more or less; it did not begin, nor will it end, in time. In effect, common to Father, Son, and Holy Spirit is the fact that they were not created, as well as their Divinity. Common to the Son and Holy Spirit is the fact that they come from the Father. Uniquely characteristic of the Father is unbegottenness; of the Son begottenness; and of the Spirit being sent.

"On Easter" by St. Gregory of Nazianzus (ca 329-389 AD)

Another Easter Homily by one of Cappadocian Fathers, St. Gregory of Nazianzus or Gregory the Theologian.

It is the Day of the Resurrection. Let us then keep the Festival with splendor and let us embrace one another.  Let us say Brethren, even to those who hate us; much more to those who have done or suffered anything out of love for us.  Let us forgive all offences for the Resurrection’s sake:  let us give one another pardon.

Yesterday the Lamb was slain and the door-posts were anointed and Egypt bewailed her Firstborn, and the Destroyer passed us over, and the Seal was dreadful and reverend, and we were walled in with the Precious Blood.  To-day we have clean escaped from Egypt and from Pharaoh; and there is none to hinder us from keeping a Feast to the Lord our God—the Feast of our Departure; or from celebrating that Feast, not in the old leaven of malice and wickedness, but in the unleavened bread of sincerity and truth, carrying with us nothing of ungodly and Egyptian leaven.

Yesterday I was crucified with Him; today I am glorified with Him; yesterday I died with Him; to-day I am quickened with Him; yesterday I was buried with Him; to-day I rise with Him.  But let us offer to Him Who suffered and rose again for us—you will think perhaps that I am going to say gold, or silver, or woven work or transparent and costly stones, the mere passing material of earth, that remains here below, and is for the most part always possessed by bad men, slaves of the world and of the Prince of the world.  Let us offer ourselves, the possession most precious to God, and most fitting; let us give back to the Image what is made after the Image.  Let us recognize our Dignity; let us honor our Archetype; let us know the power of the Mystery, and for what Christ died.

Let us become like Christ, since Christ became like us.  Let us become God’s for His sake, since He for ours became Man.  He assumed the worse that He might give us the better; He became poor that we through His poverty might be rich; He took upon Him the form of a servant that we might receive back our liberty; He came down that we might be exalted; He was tempted that we might conquer; He was dishonored that He might glorify us; He died that He might save us; He ascended that He might draw to Himself us, who were lying low in the Fall of sin.  Let us give all, offer all, to Him Who gave Himself a Ransom and a Reconciliation for us.  But one can give nothing like oneself, understanding the Mystery, and becoming for His sake all that He became for ours.

As you see, He offers you a Shepherd; for this is what your Good Shepherd, who lays down his life for his sheep, is hoping and praying for, and he asks from you his subjects; and he gives you himself double instead of single, and he adds to the inanimate temple a living one; Do you on your side offer to God obedience dwelling in a place of herbage, and being fed by water of refreshment; knowing your Shepherd well, and being known by him; and following when he calls you as a Shepherd frankly through the door; but not following a stranger climbing up into the fold like a robber and a traitor; nor listening to a strange voice when such would take you away by stealth and scatter you from the truth on mountains into deserts, and pitfalls, and places which the Lord does not visit; and would lead you away from the sound Faith in the Father, the Son, and the Holy Ghost, the One Power and Godhead, but with deceitful and corrupt words would tear them from their True Shepherd Whose Voice my sheep always heard (and may they always hear it), to a a poisoned and deadly pasture from which may we all be kept, guiding and being guided far away from it, that we may all be one in Christ Jesus our Lord, now and unto the heavenly rest.  To Whom be the glory and the might for ever and ever.  Amen.