IX.  What then, say they, is there lacking to the Spirit which prevents His being a Son, for if there were not something lacking He would be a Son?  We assert that there is nothing lacking—for God has no deficiency.  But the difference of manifestation, if I may so express myself, or rather of their mutual relations one to another, has caused the difference of their Names.  For indeed it is not some deficiency in the Son which prevents His being Father (for Sonship is not a deficiency), and yet He is not Father.  According to this line of argument there must be some deficiency in the Father, in respect of His not being Son.  For the Father is not Son, and yet this is not due to either deficiency or subjection of Essence; but the very fact of being Unbegotten or Begotten, or Proceeding has given the name of Father to the First, of the Son to the Second, and of the Third, Him of Whom we are speaking, of the Holy Ghost that the distinction of the Three Persons may be preserved in the one nature and dignity of the Godhead.  For neither is the Son Father, for the Father is One, but He is what the Father is; nor is the Spirit Son because He is of God, for the Only-begotten is One, but He is what the Son is.  The Three are One in Godhead, and the One Three in properties; so that neither is the Unity a Sabellian one, Sabellius, who taught at Rome during the Pontificate of Callistus, was by far the most important heresiarch of his period, and his opinions by far the most dangerous.  While strongly emphasizing the fundamental doctrine of the Divine Unity, he also admitted in terms a Trinity, but his Trinity was not that of the Catholic dogma, for he represented it as only a threefold manifestation of the one Divine Essence.  The Father, Son, and Holy Ghost are in his view only temporary phænomena, which fulfil their mission, and then return into the abstract Monad.  Dr. Schaff (Hist. of the Church, Ante-Nicene Period, p. 582) gives the following concise account of his teaching: “The unity of God, without distinction in itself, unfolds or extends itself in the course of the word’s development in three different forms and periods of revelation, and after the completion of redemption returns into Unity.  The Father reveals Himself in the giving of the Law or the Old Testament Economy (not in the creation also, which in his view precedes the Trinitarian revelation); the Son in the Incarnation; the Holy Ghost in inspiration; the revelation of the Son ends with the Ascension; that of the Spirit goes on in generation and sanctification.  He illustrates the Trinitarian revelation by comparing the Father to the disc of the sun, the Son to its enlightening power, the Spirit to its warming influence.  He is also said to have likened the Father to the body, the Son to the soul, the Holy Ghost to the spirit of man:  but this is unworthy of his evident speculative discrimination.  His view of the Logos too is peculiar.  The Logos is not identical with the Son, but is the Monad itself in its transition to Triad; that is, God conceived as vital motion and creating principle; the Speaking God, as distinguished from the Silent God.  Each Person (or Aspect—the word is ambiguous) is another Uttering; and the Three Persons together are only successive evolutions of the Logos, or world-ward aspect of the Divine Nature.  As the Logos proceeded from God, so He at last returns into Him, and the process of Trinitarian development closes.” nor does the Trinity countenance the present evil distinction.