Most of his writings treat of the Sacred Scriptures. He was an ardent admirer of Origen, and applied constantly the latter's principles of hermeneutics. Gregory is ever in quest of allegorical interpretations and mystical meanings hidden away beneath the literal sense of texts. As a rule, however, the "great Cappadocians" tried to eliminate this tendency. His "Treatise on the Work of the Six Days" follows St. Basil's Hexćmeron. Another work, "On the Creation of Man", deals with the work of the Sixth Day, and contains some curious anatomical details; it was translated into Latin by Dionysius Exiguus. His account of Moses as legislator offers much fine-spun allegorizing, and the same is true of his "Explanation of the Titles of the Psalms". In a brief tractate on the witch of Endor he says that the woman did not see Samuel, but only a demon, who put on the figure of the prophet. Besides a homily on the sixth Psalm, he wrote eight homilies on Ecclesiastes, in which he taught that the soul should rise above the senses, and that true peace is only to be found in contempt of worldly greatness. He is also the author of fifteen homilies on the Canticle of Canticles (the union of the soul with its Creator), five very eloquent homilies on the Lord's Prayer, and eight highly rhetorical homilies on the Beatitudes.
In theology Gregory shows himself more original and more at ease. Yet his originality is purely in manner, since he added little that is new. His diction, however, offers many felicitous and pleasing allusions, suggested probably by his mystical turn of mind. These grave studies were taken up by him late in life, hence he follows step by step the teaching of St. Basil and of St. Gregory of Nazianzus. Like them he defends the unity of the Divine nature and the trinity of Persons; where he loses their guidance, our confidence in him tends to decrease. In his teaching on the Eucharist he appears really original; his Christological doctrine, however, is based entirely on Origen and St. Athanasius. The most important of his theological writings is his large "Catechesis", or "Oratio Catechetica", an argumentative defence in forty chapters of Catholic teaching as against Jews, heathens, and heretics. The most extensive of his extant works is his refutation of Eunomius in twelve books, a defence of St. Basil against that heretic, and also of the Nicene Creed against Arianism; this work is of capital importance in the history of the Arian controversy. He also wrote two works against Apollinaris of Laodicea, in refutation of the false doctrines of that writer, viz. That the body of Christ descended from heaven, and that in Christ, the Divine Word acted as the rational soul. Among the works of Gregory are certain "Opuscula" on the Trinity addressed to Ablabius, the tribune Simplicius, and Eustathius of Sebaste. He wrote also against Arius and Sabellius, and against the Macedonians, who denied the divinity of the Holy Spirit; the latter work he never finished. In the "De anima et resurrectione" we have a dialogue between Gregory and his deceased sister, Macrina; it treats of death, resurrection, and our last end. He defends human liberty against the fatalism of the astrologers in a work "On Fate", and in his treatise "On Children", dedicated to Hieros, Prefect of Cappadocia, he undertook to explain why Providence permits the premature death of children.
He wrote also on Christian life and conduct, e.g. "On the meaning of the Christian name or profession", addressed to Harmonius, and "On Perfection and what manner of man the Christian should be", dedicated to the monk Olympius. For the monks, he wrote a work on the Divine purpose in creation. His admirable book "On Virginity", written about 370, was composed to strengthen in all who read it the desire for a life of perfect virtue.
Sermons and Homilies
Gregory wrote also many sermons and homilies, some of which we have already mentioned; others of importance are his panegyric on St. Basil, and his sermons on the Divinity of the Son and of the Holy Ghost.
A few of his letters (twenty-six) have survived; two of them offer a peculiar interest owing to the severity of his strictures on contemporary pilgrimages to Jerusalem.
For a discussion of his peculiar doctrine concerning the general restoration (Apocatastasis) to divine favour of all sinful creatures at the end of time, i.e. the temporary nature of the pains of hell, see the articles APOCATASTASIS and MIVART. The theory of interpolation of the writings of Gregory and of Origen, sustained among others by Vincenzi (below), seems, in this respect at least, both useless and gratuitous (Bardenhewer).
The writings of Gregory are best collected in P.G., XLIV-XLVI. There is no critical edition as yet, though one was begun by FORBES and OEHLER (Burntisland, 1855, 61); of another edition planned by Oehler, only one volume appeared (Halle, 1865). The best of the earlier editions is that of FRONTO DUCĆUS (Paris, 1615). Cf. VINCENZI, In Gregorii Nysseni et Origenis scripta et doctrinam nova recensio, etc. (Rome, 1864-69); BAUER, Die Trostreden des Gregorios von Nyssa in ihrem Verhältniss zur antiken Rhetorik (Marburg, 1892); BOUËDRON, Doctrines philosophiques de Saint Grégoire de Nysse (Nantes, 1861); KOCH, Das mystische Schauen beim hl. Gr. V. Nyssa in Theol. Quartalschrift (1898), LXXX, 397-420; DIEKAMP, Die Gotteslehre des hl. Gregor von Nyssa: ein Beitrag zur Dogmengesch. Der patristischen Zeit (Münster, 1897); WEISS, Die Erziehungslehre der Kappadozier (Freiburg, 1903); HILT, St. Gregorii episcopi Nysseni doctrina de angelis exposita (Freiburg, 1860); KRAMPF, Der Urzustand des Menschen nach der Lehre des hl. Gregor von Nyssa, eine dogmatisch-patristische Studie (Würzburg, 1889); REICHE, Die kunstlerischen Elemente in der Welt und Lebens-Anschauung des Gregor von Nyssa (Jena, 1897); and on the large Catechesis (logos katechetikos ho megas), generally known as Oratio Catechetica, see SRAWLEY in Journal of Theol. Studies (1902), III, 421-8, also his new edition of the Oratio (Cambridge, 1903). For an English version of several works of Gregory see Library of Nicene and Post-Nicene Fathers, second series (New York, 1893), II, v; and for a German version of some works, HAYD in the Kemptener Bibliothek der Kirchenväter (1874).
1 -[Saint Gregory of Nyssa]
2 -[Saint Gregory of Nyssa : Life]
3 -[Saint Gregory of Nyssa : Works]
4 -[Saint Gregory of Nyssa : L’homme des conciles, le conseiller du Prince]
5 -[Saint Gregory of Nyssa : Le recueillement des jours, le partage spirituel]