When Jesus Became God is a very readable and informative account of the course run in the 4th century by the Arian controversy and the church councils called to deal with it. However, the book is controversial among conservative Christians—not for its historical content but for its title and for the premises of the author. The author is a Jew who naturally does not accept either the doctrine of the New Testament or its historical claim of (among others) the bodily resurrection of Jesus; he therefore writes from the perspective that the doctrine and history of the Christian church from its very beginning after the crucifixion of Jesus can be completely explained by merely natural causes and merely human behavioral responses to other historical events.
The author, being Jewish, was raised in a religion that explicitly teaches against Jesus' resurrection, Messiahship, deity, and ability to grant the forgiveness of sins, so the author was intellectually opposed to the central articles of doctrine taught by the Christian church before he ever contemplated writing a book about its 4th century conflicts and its entanglement with the state. Much like atheistic scholars of religion, he is explaining those problems from the perspective of those who do not accept the divine origins of either the church or the New Testament (and, depending on which branch of Judaism to which he belongs, maybe not even the divine origins of the Old Testament), believing the church and its doctrine to be instead merely human creations that have little or no continuity with whatever it was that the historical Jesus and his first disciples actually taught (which in their view can't really be known at this point anyway, since they discount most of the New Testament books as later creations of Christian communities defending varying and often conflicting views of Christian life and teaching), much less with God's true and real work on earth. In this view, the church's doctrine is seen as determined mainly by earthly philosophical and political forces; it is taken for granted that the Bible can't really be used as an authoritative standard of teaching that can determine the truth or falsehood of any given doctrinal claim in history.
I'm not saying that the author writes with conscious dishonesty or malice—I'm saying that he writes with the presuppositions entirely natural to his upbringing, education, and religion, and that the reader should take that fact into consideration. If that allowance is made, the reader can get much of historical value out of this book concerning church history during the period of the Arian controversy.
On the other hand, and as with any book of course, it shouldn't be made the only source of one's knowledge about the history of the church and its teaching concerning Jesus' divinity; nor should all of the author's historical claims, especially those about the nature of the church and its teaching before the Arian controversy, be taken at face value. In fact, one of his key claims about early church history is, frankly, so outlandish that it would be comic were it not for the serious issues regarding faith, salvation, and eternal life underlying it. He writes in his Preface that
...before [the Arian controversy] ended, Jews and Christians could talk to each other and argue among themselves about crucial issues like the divinity of Jesus, the meaning of salvation, basic ethical standards...everything. They disagreed strongly about many things, but there was still a closeness between them... When the controversy ended - when Jesus became God - that closeness faded. To Christians God became a Trinity. Heresy became a crime. Judaism became a form of infidelity.
This is an incredible claim, and it is impossible to accept for those who read the New Testament as being a factual historical account. There it is obvious that the Jews were in fact not only closed to talking with Christians about Jesus' divinity but were violently hostile to such a suggestion even in Jesus' own lifetime before the Christian church was formally established at Pentecost:
John 5:16-18: And therefore did the Jews persecute Jesus, and sought to slay him, because he had done these things on the sabbath day. But Jesus answered them, My Father worketh hitherto, and I work. Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God.
And the Jews did of course later succeed in moving the Roman state to execute the one they suspected of claiming both Messiahship and deity - hardly a sign of "closeness" in spite of "strong disagreement."
John 8:48-59: Then answered the Jews, and said unto him, Say we not well that thou art a Samaritan, and hast a devil?
Jesus answered, I have not a devil; but I honour my Father, and ye do dishonour me. And I seek not mine own glory: there is one that seeketh and judgeth. Verily, verily, I say unto you, If a man keep my saying, he shall never see death.
Then said the Jews unto him, Now we know that thou hast a devil. Abraham is dead, and the prophets; and thou sayest, If a man keep my saying, he shall never taste of death. Art thou greater than our father Abraham, which is dead? and the prophets are dead: whom makest thou thyself?
Jesus answered, If I honour myself, my honour is nothing: it is my Father that honoureth me; of whom ye say, that he is your God: Yet ye have not known him; but I know him: and if I should say, I know him not, I shall be a liar like unto you: but I know him, and keep his saying. Your father Abraham rejoiced to see my day: and he saw it, and was glad.
Then said the Jews unto him, Thou art not yet fifty years old, and hast thou seen Abraham?
Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.
Then took they up stones to cast at him: but Jesus hid himself, and went out of the temple, going through the midst of them, and so passed by.
John 10:30-33: [Jesus said] I and my Father are one.
Then the Jews took up stones again to stone him.
Jesus answered them, Many good works have I shewed you from my Father; for which of those works do ye stone me?
The Jews answered him, saying, For a good work we stone thee not; but for blasphemy; and because that thou, being a man, makest thyself God.
Difficult Christian/Jewish relations persisted, to put it mildly, in such events as the stoning of Stephen, the first Christian martyr; and then later still when "another gospel" of Christ, preached by a Judaizing party actually within the church, was condemned as false doctrine by the apostle Paul in the strongest possible terms:
Gal 1:6-9, 3:1-2: I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: Which is not another; but there be some that trouble you, and would pervert the gospel of Christ. But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.
These verses establish that, contrary to the author's remarks, Judaism was "a form of infidelity" in Christian eyes, and vice versa, from the first. There was no irenic early period in which Christian teachers and Jewish teachers placidly talked over the doctrine of the church while agreeing to disagree, as the author would have us believe. False doctrine (whether of the Judaizing kind or any other) was always a matter taken extremely seriously by the church, beginning with Jesus and the apostles themselves. In a world that's fallen and in unknowing bondage to sin, death, and Satan, the declaration of the truth is inherently polarizing; therefore it's not surprising that from the very first, beginning right in the years described by the New Testament, Christian teaching has been dealing with doctrinal adversaries from within and without. Arianism has been perhaps the most serious and persistent of those adversaries. This book does a good job of showing why.
...O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you? This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith?
Orthodoxy and Arianism
As we've already seen, in the author's view the only kind of orthodoxy that has ever existed in the church has been a politically-motivated and politically-established orthodoxy, the beginnings of which date from the reign of Constantine the Great as sole Emperor (324-337; he had been Augustus of the West from 306-324). The author disbelieves in even the possibility of Biblically orthodox doctrine in the church not only because he quite matter-of-factly disbelieves in the divine inspiration, truth, and coherency of the Bible (or at least of the New Testament), but also because he doesn't believe fidelity to the Bible was what motivated the leaders of the church. He believes they were motivated by preservation of the institutional church and of their own places in it. Though he does give passing acknowledgment that both parties in the Arian controversy were also motivated by religious ideas they thought to be "the Truth," he locates their primary motivation in their desire to capitalize on those religious ideas in order to attain social stability, or where that possibility is lacking (as it was in the late Roman Empire), to attain instead personal security through a strong institutional church that preaches the reassuring things they want to hear by offering spiritual power and personal immortality in spite of the social instability of their world.
This is the cynical view of Christian faith and doctrine that sets the stage and erects the backdrop for the playing out of the Arian controversy in this book. The message preached by the church is, in this view, not the eternal, divine Word of God that has power in itself to impart saving faith in Jesus and to convert, really and truly, men's souls from death to life, a message which the church must be careful to preserve from the error that will always seek to subvert faith and thus divert men from salvation; instead, the church's message is merely a changing interpretation of what Jesus and the Bible meant, devised by human teachers according to varying philosophies, the conditions of the times those teachers lived in, and what they "needed" Jesus to be to them. In any given doctrinal conflict, the two sides are not seen as they are in the New Testament as the saving truth of God versus the deceiving errors of Satan, the adversary of both God and the Christian, but rather as the more viable and the less viable, or perhaps as the more popular and less popular, solution for the changing issues at stake in any given historical era.
Nevertheless, even under this view, the author's explanation of Arianism and its differences from orthodoxy is interesting and instructive. Arianism, he says, was the doctrine of those Christians attracted by reason, Greek logic, and a desire to see most of all in Jesus a human moral example:
Why did the Arians maintain so vehemently that God sent us a Savior who was less than God? Because, fundamentally, the idea of the Eternal becoming a man offended them, as it offended the Jews. They thought that identifying Jesus as God lowered the Almighty by embodying him in a physical creature.
Orthodoxy in Arius' time, on the other hand, is, first of all, never called orthodoxy by the author. The political orthodoxy of which he writes didn't quite exist yet, and as I've already pointed out, he believes there was no doctrinal, Biblical orthodoxy in the church to which a teaching could be said to conform or from which it could be said to deviate.
...The Arians, furthermore, had become prisoners of Greek logic. They thought in terms of either/or. That is why they accused Alexander [Bishop of Alexandria and mentor of Athanasius] and his allies of "Sabellianism": a heresy asserting that God and Jesus were simply aspects of (or names for) the same undivided reality...Arius was right to reject this thinking, Athanasius said, but in doing so he had fallen into the opposite trap. Either/or: either Jesus was really God or he was really human. The Arians could not really imagine that he might be both, and so the tendency of their thought (even though they denied it) was to turn him into a man - or into some sort of third creature, an angel or demigod.
Those whose ideas and social relationships were still shaped to a large extent by the optimistic ideals and tolerant practices of pagan society, and for whom Christianity seemed a natural extension of and improvement on Judaism, tended to be Arians of one sort or another.
[The vision of Arius' Jesus was that of] "a beacon of moral progress sent not so much to rescue helpless humans [allegedly the view held by the orthodox of Jesus], as to inspire them to develop their own potential for divinity.
I nevertheless differ from the author in that view, and so refer here to those who opposed Arianism as the "orthodox" because it is clear the church as a whole had been combating "Arianism" (if we take it in the broad sense used by the author above on page 63 of his book as being the theological tendency of those offended by the idea of God becoming a man) since the New Testament era itself. The Jews shown in the New Testament of course totally rejected the idea that Jesus, a man, could be the same in any sense as the one true God of Israel. The author himself, as quoted above, notes the tendency of Judaizing parties in the church to prefer a more human rather than a more divine Jesus. In similar ways, though the author does not mention it, several teachers well before Arius, who was born around A.D. 250 and died in A.D. 337, had already been excommunicated for teaching that Jesus was less than the one true God.
Marcion, who is known as the first great heretic and who died around A.D. 160, taught that Jesus had only an apparent body of flesh and blood. Being a lesser but still divine emissary from the Father, Jesus could not really have been incarnate in evil matter, according to Marcion. His Christology was docetic and had gnostic tendencies, in other words; and it was decisively rejected by the church of his day when he was excommunicated in A.D. 144 in Rome. According to the Oxford Dictionary of the Christian Church, Dionysius of Corinth, Irenaeus of Lyons, Theophilus of Antioch, Philip of Gortyna, Tertullian at Carthage, Hippolytus and Rhodo at Rome, and Bardesanes at Edessa all wrote against him as being a heretic.
Theodotus the Tanner, usually cited as the originator of Adoptionism, the teaching that Jesus was a man who was elevated by the indwelling of the Spirit at his baptism by John to the status of God, was excommunicated by Victor of Rome around A.D. 190. Another Theodotus, called Theodotus the Money-Changer, who is said to have taught much the same thing as the first Theodotus, was excommunicated about ten years later by Zephyrinus, Victor's successor.
Later, but still before Arius, a teacher named Paul of Samosata (c. A.D. 200 - A.D. 275), was condemned by a council meeting in Antioch in 268. He taught
...a more sophisticated view...He did call Jesus God, unlike the earlier adoptionists for whom He was a mere man, but by this Paul only meant that through his moral perfection and the miraculous powers granted him at his baptism, Jesus was able to remain in constant union with God.
On the other hand, the church had also been vigilant to guard against the opposite tendency as well - the teaching known as Modalism, which made no distinction at all between the Father, the Son, and the Holy Spirit, teaching that they were somehow or other merely successive modes of being of the one true God. The first one known to have taught this, Noetus, was condemned by an assembly of elders in Smyrna around A.D. 200.
(Heresies by Harold O.J. Brown, Hendrickson Publishers, Peabody, Massachusetts, 2000, p. 98)
Thus the concept of "heresy" was not newly introduced in the fourth century, suddenly enforced under the banner of a merely political orthodoxy invented at Nicea under pressure from a Emperor who wished to unify his empire. Nor were excommunications for heretical teaching unknown before that. Rather, the church knew from its beginnings in the pages of the New Testament itself that it would be faced with deceivers teaching "another Jesus." (2 Corinthians 11:4) or "another gospel" (2 Corinthians 11:4 again, and also Galatians 1:6) that could pervert the true gospel of Christ and divide the church. Christians were enjoined by the New Testament to mark and avoid such men:
Romans 16:17: Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them.
With that qualification, one can nevertheless agree with the author that Arianism was perhaps the greatest conflict the church experienced prior to the Reformation, and can also appreciate his telling of its history. Though it was never doctrinally significant in the western half of the Roman Empire, Arianism deeply divided the eastern half, and for a time, under Constantine's son and successor Constantius, even succeeded in becoming the politically-enforced "orthodoxy" of the entire Empire. The way that happened, and the way the church recovered from it, is complex, but the author does a good job of telling the story and giving a clear picture of the numerous events, names, dates, and shifting party alliances (both political and theological) involved in that conflict.