Daily Reading for May 30 • Trinity Sunday
I have already said that God reared this fabric of the world out of nothing, by his word, wisdom, or power; and it is evident that your sages of old were of the same opinion, that the Ao’yos, that is, the Word, or the Wisdom, was the Maker of the universe, for Zeno determines the Logos to be the creator and adjuster of everything in nature. The same Logos he affirms to be called by the name of Fate, God, Mind of Jove, and Necessity of all Things. Cleanthes will have the author of the world to be a spirit which pervades every part of it. And we Christians also do affirm a spirit to be the proper substance of the Logos, by whom all things were made, in which he subsisted before he was spoken out, and was the wisdom that assisted at the creation, and the power that presided over the whole work. The Logos or Word issuing forth from that spiritual substance at the creation of the world, and generated by that issuing or progression, is for this reason called the Son of God, and the God, from his unity of substance with God the Father, for God is a Spirit.
An imperfect image of this you have in the derivation of a ray from the body of the sun; for this ray is a part without any diminution of the whole, but the sun is always in the ray, because the ray is always from the sun; nor is the substance separated, but only extended. Thus is it in some measure in the eternal generation of the Logos; he is a spirit of a spirit, a God of God, as one light is generated by another; the original parent light remaining entire and undiminished, notwithstanding the communication of itself to many other lights. Thus it is that the Logos which came forth from God is both God and the Son of God, and those two are one. Hence it is that a spirit of a spirit, or a God of God, makes another in mode of subsistence, but not in number; in order of nature, but not in numericalness or identity of essence; and so the Son is subordinate to the Father as he comes from him as the principle, but is never separated. This ray of God then descended, as it was foretold, upon a certain Virgin, and in her womb was incarnated, and being there fully formed the God-man, was born into the world; the divine and human nature making up this person, as soul and body does one man. The flesh being wrought and perfected by a divine Spirit, was nursed and grew up to the stature of a man, and then addressed the Jews, and preached and worked miracles among them; and this is the Christ, the God of Christians.
From The Apology of Tertullian, translated by William Reeve, A.M., volume 31 of The Ancient & Modern Library of Theological Literature. Found at http://www.tertullian.org/articles/reeve_apology.htm