This is the perfect Trinity, Which knows no division nor estrangement in respect to Its shared glory, immortality, and sovereignty.
At that time, the teaching of Paul of Samosata began to spread everywhere, and since Gregory was uncertain how to regard it, he began to pray fervently to God and the Mother of God to reveal to him the truth concerning the doctrine of the Holy Trinity. One night, while he was praying ardently, the most pure Virgin Mary appeared to him, radiant as the son, and the company of Saint John the Theologian, was clothed in a bishop’s garments. Pointing to Gregory with her hand, the most pure Virgin commanded Saint John to instruct him in the correct teaching concerning the mystery of the Holy Trinity. By the command of the Mother of God, Saint Gregory drew from the inexhaustible depth of wisdom, quickly learning the great mysteries of God from Saint John the Theologian. The words of revelation spoken by John were these: “There is one God, the Father of the living Word, the hypostatic Wisdom, Power, and the Father’s eternal Image: the perfect Begetter of Him who is perfect, Father of the only-begotten Son. There is one Lord, one God of one God, the Imprint and Image of the Divinity, creative Word, Wisdom which sustains everything that exists, the Power which has made all creation, true Son of the true Father, unseen Son of the invisible Father, incorruptible Offspring of the incorruptible One, immortal and eternal Child of the everlasting One. There is one Holy Spirit, who has His beginning from the Father and is revealed unto men through the Son. He is the perfect Image of the perfect Son, the Source of life for all things, the sacred Fountain in Whom God the Father and God the Son are revealed. He is at once above all and in all, and fills all things. This is the perfect Trinity, Which knows no division nor estrangement in respect to Its shared glory, immortality, and sovereignty.
There is nothing created in the Trinity or subject to another or brought from without, as though once non-existent in later introduced, for at no time did the Father exist without the Son or the Son without the Spirit, because the Trinity abides forever unchanged, without variation or mutation.
After seeing this vision, Saint Gregory wrote out with his own hand the words Saint John the Theologian had spoken in him. This record was preserved for many years in the Church of Neo-Caesarea.