Born in Nazianzus of a Greek father (who later became a Christian and a bishop) and a Christian mother, he studied in Athens before his baptism with Basil the Great and Julian the Apostate. He often foretold to Julian that he would become an apostate and a persecutor of the Church, and so it came to pass. Gregory was especially influenced by his mother Nonna. He was baptized when he had completed his studies. Saint Basil the Great consecrated him bishop of Sasima, and the Emperor Theodosius quickly called him to the vacant archiepiscopal throne of Constantinople.

His works were manifold, the best-known being his theological writings, for which he received the title “the Theologian.”

He is particularly famed for the depth of his sermons on the Holy Trinity. He also wrote against the heretic Macedonius, who taught wrongly of the Holy Spirit (that the Spirit was a creature of God), and against  Apollinaris who taught that Christ did not have a human soul but that His divinity was in place of His soul. He also wrote against the Emperor Julian the Apostate, his sometime schoolfellow.

In the year 381, when a quarrel broke out in the Council concerning his election as archbishop, he withdrew himself, declaring:

“Those who deprive us of the archiepiscopal throne cannot deprive us of God.”

He then left Constantinople and went to Nazianzus, remaining in retirement, prayer and writing instructive books until his death. And, although he was in weak health all his life, he lived to the age of seventy.

His relics were later taken to Rome, and his head to the Cathedral of the Dormition in Moscow. He was, and remains, a great and wonderful light of the Orthodox Church, as much for the meekness and purity of his character as for the unsurpassable depth of his mind. He entered into rest in the Lord in the year 389. He is revered in the Orthodox Church as one of the "Three Holy Hierarchs", along with Basil the Great and John Chrysostom.

From the Prologue From Ochrid, St. Nicholas of South Canaan

Saint Gregory the Theologian, Archbishop of Constantinople, a great Father and teacher of the Church, was born into a Christian family of eminent lineage in the year 329, at Arianzos (not far from the city of Cappadocian Nazianzos). His father, also named Gregory (January 1), was Bishop of Nazianzus. The son is the St. Gregory Nazianzus encountered in Patristic theology. His pious mother, St. Nonna (August 5), prayed to God for a son, vowing to dedicate him to the Lord. Her prayer was answered, and she named her child Gregory.

When the child learned to read, his mother presented him with the Holy Scripture. St. Gregory received a complete and extensive education: after working at home with his uncle St. Amphilochios, an experienced teacher of rhetoric, he then studied in the schools of Nazianzos, Caesarea in Cappadocia, and Alexandria. Then the saint decided to go to Athens to complete his education.

On the way from Alexandria to Greece, a terrible storm raged for many days. St. Gregory, who was just a catechumen at that time, feared that he would perish in the sea before being cleansed in the waters of Baptism. St. Gregory lay in the ship's stern for twenty days, beseeching the merciful God for salvation. He vowed to dedicate himself to God, and was saved when he invoked the name of the Lord.

St. Gregory spent six years in Athens studying rhetoric, poetry, geometry, and astronomy. His teachers were the reknowned pagan rhetoricians Gymorias and Proeresias. St. Basil, the future Archbishop of Caesarea (January 1) also studied in Athens with St. Gregory. They were such close friends that they seemed to be one soul in two bodies. Julian, the future emperor (361-363) and apostate from the Christian Faith, was studying philosophy in Athens at the same time.

Upon completing his education, St. Gregory remained for a certain while at Athens as a teacher of rhetoric. He was also familiar with pagan philosophy and literature.

In 358 St. Gregory quietly left Athens and returned to his parents at Nazianzus. At thirty-three years of age, he received Baptism from his father, who had been appointed Bishop of Nazianzus. Against his will, St. Gregory was ordained to the holy priesthood by his father. However, when the elder Gregory wished to make him a bishop, he fled to join his friend Basil in Pontus. St. Basil had organized a monastery in Pontus and had written to Gregory inviting him to come.

St. Gregory remained with St. Basil for several years. When his brother St. Caesarius (March 9) died, he returned home to help his father administer his diocese. The local church was also in turmoil because of the Arian heresy. St. Gregory had the difficult task of reconciling the bishop with his flock, who condemned their pastor for signing an ambiguous interpretation of the dogmas of the faith.

St. Gregory convinced his father of the pernicious nature of Arianism, and strengthened him in Orthodoxy. At this time, Bishop Anthimos, who pretended to be Orthodox but was really a heretic, became Metropolitan of Tyana. St. Basil had been consecrated as the Archbishop of Caesarea, Cappadocia. Anthimos wished to separate from St. Basil and to divide the province of Cappadocia.

St. Basil the Great made St. Gregory bishop of the city of Sasima, a small town between Caesarea and Tyana. However, St. Gregory remained at Nazianzos in order to assist his dying father, and he guided the flock of this city for a while after the death of his father in 374.

Upon the death of Patriarch Valentus of Constantinople in the year 378, a council of bishops invited St. Gregory to help the Constantinople Church, which at this time was ravaged by heretics. Obtaining the consent of St. Basil the Great, St. Gregory came to Constantinople to combat heresy. In the year 379 he began to serve and preach in a small church called "Anastasis" ("Resurrection"). Like David fighting the Philistines with a sling, St. Gregory battled against impossible odds to defeat false doctrine.

Heretics were in the majority in the capital, Arians, Macedonians, and Appolinarians. The more he preached, the more did the number of heretics decrease, and the number of the Orthodox increased. On the night of Pascha (April 21, 379) when St. Gregory was baptizing catechumens, a mob of armed heretics burst into the church and cast stones at the Orthodox, killing one bishop and wounding St. Gregory. But the fortitude and mildness of the saint were his armor, and his words converted many to the Orthodox Church.

St. Gregory's literary works (orations, letters, poems) show him as a worthy preacher of the truth of Christ. He had a literary gift, and the saint sought to offer his talent to God the Word: "I offer this gift to my God, I dedicate this gift to Him. Only this remains to me as my treasure. I gave up everything else at the command of the Spirit. I gave all that I had to obtain the pearl of great price. Only in words do I master it, as a servant of the Word. I would never intentionally wish to disdain this wealth. I esteem it, I set value by it, I am comforted by it more than others are comforted by all the treasures of the world. It is the companion of all my life, a good counselor and converser; a guide on the way to Heaven and a fervent co-ascetic." In order to preach the Word of God properly, the saint carefully prepared and revised his works.

In five sermons, or "Theological Orations," St. Gregory first of all defines the characteristics of a theologian, and who may theologize. Only those who are experienced can properly reason about God, those who are successful at contemplation and, most importantly, who are pure in soul and body, and utterly selfless. To reason about God properly is possible only for one who enters into it with fervor and reverence.

Explaining that God has concealed His Essence from mankind, St. Gregory demonstrates that it is impossible for those in the flesh to view mental objects without a mixture of the corporeal. Talking about God in a positive sense is possible only when we become free from the external impressions of things and from their effects, when our guide, the mind, does not adhere to impure transitory images. Answering the Eunomians, who would presume to grasp God's Essence through logical speculation, the saint declared that man perceives God when the mind and reason become godlike and divine, i.e. when the image ascends to its Archetype. (Or. 28:17). Furthermore, the example of the Old Testament patriarchs and prophets and also the Apostles has demonstrated, that the Essence of God is incomprehensible for mortal man. St. Gregory cited the futile sophistry of Eunomios: "God begat the Son either through His will, or contrary to will. If He begat contrary to will, then He underwent constraint. If by His will, then the Son is the Son of His intent."

Confuting such reasoning, St. Gregory points out the harm it does to man: "You yourself, who speak so thoughtlessly, were you begotten voluntarily or involuntarily by your father? If involuntarily, then your father was under the sway of some tyrant. Who? You can hardly say it was nature, for nature is tolerant of chastity. If it was voluntarily, then by a few syllables you deprive yourself of your father, for thus you are shown to be the son of Will, and not of your father" (Or. 29:6).

St. Gregory then turns to Holy Scripture, with particular attention examining a place where it points out the Divine Nature of the Son of God. St. Gregory's interpretations of Holy Scripture are devoted to revealing that the divine power of the Savior was actualized even when He assumed an impaired human nature for the salvation of mankind.

The first of St. Gregory's Five Theological Orations is devoted to arguments against the Eunomians for their blasphemy of the Holy Spirit. Closely examining everything that is said in the Gospel about the Third Person of the Most Holy Trinity, the saint refutes the heresy of Eunomios, which rejected the divinity of the Holy Spirit. He comes to two fundamental conclusions. First, in reading Holy Scripture, it is necessary to reject blind literalism and to try and understand its spiritual sense. Second, in the Old Testament the Holy Spirit operated in a hidden way. "Now the Spirit Himself dwells among us and makes the manifestation of Himself more certain. It was not safe, as long as they did not acknowledge the divinity of the Father, to proclaim openly that of the Son; and as long as the divinity of the Son was not accepted, they could not, to express it somewhat boldly, impose on us the burden of the Holy Spirit" (Or. 31:26).

The divinity of the Holy Spirit is a sublime subject. "Look at these facts: Christ is born, the Holy Spirit is His Forerunner. Christ is baptized, the Spirit bears witness to this... Christ works miracles, the Spirit accompanies them. Christ ascends, the Spirit takes His place. What great things are there in the idea of God which are not in His power? What titles appertaining to God do not apply also to Him, except for Unbegotten and Begotten? I tremble when I think of such an abundance of titles, and how many Names they blaspheme, those who revolt against the Spirit!" (Or. 31:29).

The Orations of St. Gregory are not limited only to this topic. He also wrote Panegyrics on Saints, Festal Orations, two invectives against Julian the Apostate, "two pillars, on which the impiety of Julian is indelibly written for posterity," and various orations on other topics. In all, forty-five of St. Gregory's orations have been preserved.

The letters of the saint compare favorably with his best theological works. All of them are clear, yet concise. In his poems as in all things, St. Gregory focused on Christ. "If the lengthy tracts of the heretics are new Psalters at variance with David, and the pretty verses they honor are like a third testament, then we also shall sing Psalms, and begin to write much and compose poetic meters," said the saint. Of his poetic gift the saint wrote: "I am an organ of the Lord, and sweetly... do I glorify the King, all atremble before Him."

The fame of the Orthodox preacher spread through East and West. But the saint lived in the capital as though he still lived in the wilderness: "his food was food of the wilderness; his clothing was whatever necessary. He made visitations without pretense, and though in proximity of the court, he sought nothing from the court."

The saint received a shock when he was ill. One whom he considered as his friend, the philosopher Maximos, was consecrated at Constantinople in St. Gregory's place. Struck by the ingratitude of Maximos, the saint decided to resign the cathedra, but his faithful flock restrained him from it. The people threw the usurper out of the city. On November 24, 380 the holy emperor Theodosius arrived in the capital and, in enforcing his decree against the heretics, the main church was returned to the Orthodox, with St. Gregory making a solemn entrance. An attempt on the life of St. Gregory was planned, but instead the assassin appeared before the saint with tears of repentance.

At the Second Ecumenical Council in 381, St. Gregory was chosen as Patriarch of Constantinople. After the death of Patriarch Meletios of Antioch, St. Gregory presided at the Council. Hoping to reconcile the West with the East, he offered to recognize Paulinus as Patriarch of Antioch.

Those who had acted against St. Gregory on behalf of Maximos, particularly Egyptian and Macedonian bishops, arrived late for the Council. They did not want to acknowledge the saint as Patriarch of Constantinople, since he was elected in their absence.

St. Gregory decided to resign his office for the sake of peace in the Church: "Let me be as the Prophet Jonah! I was responsible for the storm, but I would sacrifice myself for the salvation of the ship. Seize me and throw me... I was not happy when I ascended the throne, and gladly would I descend it."

After telling the emperor of his desire to quit the capital, St. Gregory appeared again at the Council to deliver a farewell address (Or. 42) asking to be allowed to depart in peace.

Upon his return to his native region, St. Gregory turned his attention to the incursion of Appolinarian heretics into the flock of Nazianzus, and he established the pious Eulalios there as bishop, while he himself withdrew into the solitude of Arianzos so dear to his heart. The saint, zealous for the truth of Christ continued to affirm Orthodoxy through his letters and poems, while remaining in the wilderness. He died on January 25, 389, and is honored with the title "Theologian," also given to the holy Apostle and Evangelist John.

In his works St. Gregory, like that other Theologian St. John, directs everything toward the Pre-eternal Word. St. John of Damascus (December 4), in the first part of his book AN EXACT EXPOSITION OF THE ORTHODOX FAITH, followed the lead of St. Gregory the Theologian.

St. Gregory was buried at Nazianzos. In the year 950, his holy relics were transferred to Constantinople into the church of the Holy Apostles. Later on, a portion of his relics was transferred to Rome.

In appearance, the saint was of medium height and somewhat pale. He had thick eyebrows, and a short beard. His contemporaries already called the archpastor a saint. The Orthodox Church, honors St. Gregory as a second Theologian and insightful writer on the Holy Trinity.

"O glorious Father Gregory, Your knowledge has overcome the pride of false wisdom. The church is clothed with your teaching as a robe of righteousness. We your children celebrate your memory crying out: Rejoice, O father of unsurpassable wisdom!" [Kontakion].