Troparion of St Gregory of Nyssa Tone 3
Thou hast shown forth thy watchfulness/ and wast a fervent preacher of godliness:/ by the wisdom of thy teachings thou dost gladden the Church’s faithful./ Righteous Father Gregory,/ entreat Christ our God to grant us His great mercy.
Kontakion of St Gregory Tone 1
Watchful with the eyes of thy soul/ and a vigilant shepherd for the world,/ with wisdom and thy fervent intercession thou didst drive off heretics like wolves,/ keeping thy flock unharmed.
From the OCA Website:
Saint Gregory, Bishop of Nyssa, was a younger brother of St. Basil the Great (January 1). His birth and upbringing came at a time when the Arian disputes were at their height. Having received an excellent education, he was at one time a teacher of rhetoric. In the year 372, he was consecrated by St. Basil the Great as bishop of the city of Nyssa in Cappadocia.
St. Gregory was an ardent advocate for Orthodoxy, and he fought against the Arian heresy with his brother St. Basil. Gregory was persecuted by the Arians, by whom he was falsely accused of improper use of church property, and thereby deprived of his See and sent to Ancyra.
In the following year St. Gregory was again deposed in absentia by a council of Arian bishops, but he continued to encourage his flock in Orthodoxy, wandering about from place to place. After the death of the emperor Valens (378), St. Gregory was restored to his cathedra and was joyously received by his flock. His brother St. Basil the Great died in 379.
Only with difficulty did St. Gregory survive the loss of his brother and guide. He delivered a funeral oration for him, and completed St. Basil’s study of the six days of Creation, the Hexaemeron. That same year St. Gregory participated in the Council of Antioch against heretics who refused to recognize the perpetual virginity of the Mother of God. Others at the opposite extreme, who worshipped the Mother of God as being God Herself, were also denounced by the Council. He visited the churches of Arabia and Palestine, which were infected with the Arian heresy, to assert the Orthodox teaching about the Most Holy Theotokos. On his return journey St. Gregory visited Jerusalem and the Holy Places.
In the year 381 St. Gregory was one of the chief figures of the Second Ecumenical Council, convened at Constantinople against the heresy of Macedonius, who incorrectly taught about the Holy Spirit. At this Council, on the initiative of St. Gregory, the Nicean Symbol of Faith (the Creed) was completed.
Together with the other bishops St. Gregory affirmed St. Gregory the Theologian as Archpastor of Constantinople.
In the year 383, St. Gregory of Nyssa participated in a Council at Constantinople, where he preached a sermon on the divinity of the Son and the Holy Spirit. In 386, he was again at Constantinople, and he was asked to speak the funeral oration in memory of the empress Placilla. Again in 394 St. Gregory was present in Constantinople at a local Council, convened to resolve church matters in Arabia.
St. Gregory of Nyssa was a fiery defender of Orthodox dogmas and a zealous teacher of his flock, a kind and compassionate father to his spiritual children, and their intercessor before the courts. He was distinguished by his magnanimity, patience and love of peace.
Having reached old age, St. Gregory of Nyssa died soon after the Council of Constantinople. Together with his great contemporaries, Sts. Basil the Great and Gregory the Theologian, St. Gregory of Nyssa had a significant influence on the Church life of his time. His sister, St. Macrina, wrote to him: “You are reknowned both in the cities, and gatherings of people, and throughout entire districts. Churches ask you for help.” St. Gregory is known in history as one of the most profound Christian thinkers of the fourth century. Endowed with philosophical talent, he saw philosophy as a means for a deeper penetration into the authentic meaning of divine revelation.
St. Gregory left behind many remarkable works of dogmatic character, as well as sermons and discourses. He has been called “the Father of Fathers.”
Gregory of Nyssa was born in Caesarea, the capital of Cappadocia (central Turkey) in about 334, the younger brother of Basil the Great and of Macrina (19 July), and of several other distinguished persons. As a youth, he was at best a lukewarm Christian. However, when he was twenty, some of the relics of the Forty Martyrs of Sebaste (10 March) were transferred to a chapel near his home, and their presence made a deep impression on him, confronting him with the fact that to acknowledge God at all is to acknowledge His right to demand a total commitment. Gregory became an active and fervent Christian. He considered the priesthood, decided it was not for him, became a professional orator like his father, married, and settled down to the life of a Christian layman. However, his brother Basil and his friend Gregory of Nazianzus persuaded him to reconsider, and he became a priest in about 362. (This did not affect his marriage.)
His brother Basil, who had become archbishop of Caesarea in 370, was engaged in a struggle with the Arian Emperor Valens, who was trying to stamp out belief in the deity of Christ. Basil desperately needed the votes and support of Athanasian bishops, and he maneuvered his friend Gregory into the bishopric of Sasima, and (in about 371) his brother Gregory into the bishopric of Nyssa, a small town about ten miles from Caesarea. Neither one wanted to be a bishop, neither was suited to be a bishop, and both were furious with Basil.) Gregory did not get along well with his flock, was falsely accused of embezzling church funds, fled the scene in about 376, and did not return until after the death of Valens about two years later.
In 379, Basil died, having lived to see the death of Valens and the end of the persecution. Shortly thereafter, Macrina died. Gregory was with her in the last few days of her life. Afterwards, he took to writing sermons and treatises on theology and philosophy. His philosophy was a form of Christian Platonism. In his approach to the Scriptures, he was heavily influenced by Origen, and his writings on the Trinity and the Incarnation build on and develop insights found in germ in the writings of his brother Basil. But he is chiefly remembered as a writer on the spiritual life, on the contemplation of God, not only in private prayer and meditation, but in corporate worship and in the sacramental life of the Church.
St Gregory of Nyssa, Dogmatic Treatises, Select Writings and Letters (Nicene and Post-Nicene Fathers, Second Series, v. 5)