Gregory was one of the famous Cappadocian theologians, family friend of Basil of Caesarea, Gregory of Nyssa, and their sister, Macrina. Gregory served as Bishop of Constantinople from A.D. 379 to 381, and presided over the Council of Constantinople in the year A.D. 381 (the year this sermon was preached), which re-affirmed the Creed of Nicaea, as well as expanding it to clarify the church's doctrine of the deity of the Holy Spirit, affirming the Spirit as fully God, who receives worship together with the Father and the Son.