Person

Gregory of Nyssa

Greek bishop and theologian (c. AD 335-394), one of the three Cappadocian Fathers (alongside his brother Basil the Great and friend Gregory of Nazianzus). Bishop of Nyssa (in Cappadocia, modern central Turkey) from c. 372. Played a decisive role at the Council of Constantinople (381) in finalizing Nicene Trinitarian doctrine. Author of On the Making of Man, On the Soul and Resurrection, Catechetical Oration, Life of Moses, Homilies on the Song of Songs, and Homilies on Ecclesiastes.

Theological contributions

1. Trinitarian theology

Gregory developed the Cappadocian distinction between ousia (essence, what God is) and hypostasis (person, who God is) that became the standard grammar for Eastern Trinitarian doctrine. With Basil and Gregory of Nazianzus, he secured Nicene orthodoxy against the various Arian and semi-Arian positions at Constantinople (381).

2. Mystical theology

Gregory's Life of Moses and Homilies on the Song of Songs developed the patristic theology of epektasis, the soul's endless progress into God's infinite goodness. His mystical theology emphasizes that God's incomprehensibility is not a deficit but a positive feature of the divine life: the more we know God, the more we recognize how much remains to know.

3. Anti-slavery preaching

Gregory's Fourth Homily on Ecclesiastes (commenting on Eccl 2:7, "I got me servants and maidens") contains one of the strongest anti-slavery statements from any pre-modern Christian author. He asks rhetorically: "What price did you put on rationality? How many obols did you reckon the equivalent of the likeness of God?" The argument is straightforward: a being made in God's image cannot be priced. The homily directly challenges the legitimacy of slaveholding as such, not merely its abuses, a remarkable position in the fourth-century context.

4. The image of God

Gregory's On the Making of Man develops a sophisticated account of the imago Dei, humanity made for divine participation and called to grow eternally into the divine likeness. His anti-slavery argument rests directly on this anthropology.

Mentions in Defining Chattel Slavery and Biblical Servitude (ris3n)

Cited (§8.C) for the Fourth Homily on Ecclesiastes and his pointed question: "What price did you put on rationality?", adduced as a patristic witness that the imago Dei renders human commodification incoherent.
Listed (§13, implicitly) as part of the patristic ethical trajectory by which the early Christian tradition read the gospel in tension with the Roman slave system.

Mentions in Quick-Glance Reference Guide to Aquinas Five Ways (ris3n)

Cited under the First Way (motion): "All motion has its beginning from another", adduced as a patristic precursor of the quidquid movetur, ab alio movetur principle.