Prologue. The presiding ministers of the “mystery of godliness” 1935 have need of a system in their instructions, in order that the Church may be replenished by the accession of such as should be saved 1936 , through the teaching of the word of Faith being brought home to the hearing of unbelievers. Not that the same method of instruction will be suitable in the case of all who approach the word. The catechism must be adapted to the diversities of their religious worship; with an eye, indeed, to the one aim and end of the system, but not using the same method of preparation in each individual case. The Judaizer has been preoccupied with one set of notions, one conversant with Hellenism, with others; while the Anomœan, and the Manichee, with the followers of Marcion 1937 , Valentinus, and Basilides 1938 , and the rest on the list of those who have wandered into heresy, each of them being prepossessed with their peculiar notions, necessitate a special controversy with their several. opinions. The method of recovery must be adapted to the form of the disease. You will not by the same means cure the polytheism of the Greek, and the unbelief of the Jew as to the Only-begotten God: nor as regards those who have wandered into heresy will you, by the same arguments in each case, upset their misleading romances as to the tenets of the Faith. No one could set Sabellius 1939 right by the same instruction as would benefit the Anomœan 1940 . The controversy with the Manichee is profitless against the Jew 1941 . It is necessary, therefore, as I have said, to regard the opinions which the persons have taken up, and to frame your argument in accordance with the error into which each has fallen, by advancing in each discussion certain principles and reasonable propositions, that thus, through what is agreed upon on both sides, the truth may conclusively be brought to light. When, then, a discussion is held with one of those who favour Greek ideas, it would be well to make the ascertaining of this the commencement of the reasoning, i.e. whether he presupposes the existence of a God, or concurs with the atheistic view. Should he say there is no God, then, from the consideration of the skilful and wise economy of the Universe he will be brought to acknowledge that there is a certain overmastering power manifested through these channels. If, on the other hand, he should have no doubt as to the existence of Deity, but should be inclined to entertain the presumption of a plurality of Gods, then we will adopt against him some such train of reasoning as this: “does he think Deity is perfect or defective?” and if, as is likely, he bears testimony to the perfection in the Divine nature, then we will demand of him to grant a perfection throughout in everything that is observable in that divinity, in order that Deity may not be regarded as a mixture of opposites, defect and perfection. But whether as respects power, or the conception of goodness, or wisdom and imperishability and eternal existence, or any other notion besides suitable to the nature of Deity, that is found to lie close to the subject of our contemplation, in all he will agree that perfection is the idea to be entertained of the Divine nature, as being a just inference from these premises. If this, then, be granted us, it would not be difficult to bring round these scattered notions of a plurality of Gods to the acknowledgment of a unity of Deity. For if he admits that perfection is in every respect to be ascribed to the subject before us, though there is a plurality of these perfect things which are marked with the same character, he must be required by a logical necessity, either to point out the particularity in each of these things which present no distinctive variation, but are found always with the same marks, or, if (he cannot do that, and) the mind can grasp nothing in them in the way of particular, to give up the idea of any distinction. For if neither as regards “more and less” a person can detect a difference (in as much as the idea of perfection does not admit of it), nor as regards “worse” and “better” (for he cannot entertain a notion of Deity at all where the term “worse” is not got rid of), nor as regards “ancient” and “modern” (for what exists not for ever is foreign to the notion of Deity), but on the contrary the idea of Godhead is one and the same, no peculiarity being on any ground of reason to be discovered in any one point, it is an absolute necessity that the mistaken fancy of a plurality of Gods would be forced to the acknowledgment of a unity of Deity. For if goodness, and justice, and wisdom, and power may be equally predicated of it, then also imperishability and eternal existence, and every orthodox idea would be in the same way admitted. As then all distinctive difference in any aspect whatever has been gradually removed, it necessarily follows that together with it a plurality of Gods has been removed from his belief, the general identity bringing round conviction to the Unity. 1935     1 Tim. iii. 16 . 1936     Acts ii. 47 . 1937     Marcion, a disciple of Cerdo, added a third Principle to the two which his master taught. The first is an unnamed, invisible, and good God, but no creator; the second is a visible and creative God, i.e. the Demiurge; the third intermediate between the invisible and visible God, i.e. the Devil. The Demiurge is the God and Judge of the Jews. Marcion affirmed the Resurrection of the soul alone. He rejected the Law and the Prophets as proceeding from the Demiurge; only Christ came down from the unnamed and invisible Father to save the soul, and to confute this God of the Jews. The only Gospel he acknowledged was S. Luke’s, omitting the beginning which details our Lord’s Conception and Incarnation. Other portions also both in the middle and the end he curtailed. Besides this broken Gospel of S. Luke he retained ten of the Apostolic letters, but garbled even them. Gregory says elsewhere that the followers of Eunomius got their “duality of Gods” from Marcion, but went beyond him in denying essential goodness to the Only-begotten, the “God of the Gospel.” 1938     Of the Gnostics Valentinus and Basilides the truest and best account is given in H. L. Mansel’s Gnostics, and in the articles upon them in the Dictionary of Christian Biography. It is there shown how all their visions of celestial Hierarchies, and the romances connected with them, were born of the attempt to solve the insoluble problem, i.e. how that which in modern philosophy would be called the Infinite is to pass into the Finite. They fell into the fatalism of the Emanationist view of the Deity, but still the attempt was an honest one. 1939     Sabellius. The Sabellian heresy was rife in the century preceding: i.e. that Personality is attributed to the Deity only from the exigency of human language, that consequently He is sometimes characterized as the Father, when operations and works more appropriate to the paternal relation are spoken of; and so in like manner of the Son, and the Holy Ghost; as when Redemption is the subject, or Sanctification. In making the Son the Father, it is the opposite pole to Arianism. 1940     “We see also the rise ( i.e. a.d. 350) of a new and more defiant Arian school, more in earnest than the older generation, impatient of their shuffling diplomacy, and less pliant to court influences. Aetius.…came to rest in a clear and simple form of Arianism. Christianity without mystery seems to have been his aim. The Anomœan leaders took their stand on the doctrine of Arius himself and dwelt with emphasis on its most offensive aspects. Arius had long ago laid down the absolute unlikeness of the Son to the Father, but for years past the Arianizers had prudently softened it down. Now, however, ‘unlike’ became the watchword of Aetius and Eunomius”: Gwatkin’s Arians. For the way in which this school treated the Trinity see Against Eunomius, p. 50. 1941     I.e. an argument against Dualism would only confirm the Jew in his stern monotheism. Manes had taught also that “those souls who believe Jesus Christ to be the Son of God renounce the worship of the God of the Jews, who is the Prince of Darkness,” and that “the Old Testament was the work of this Prince, who was substituted by the Jews in the place of the true God.”