It's easy to get the impression that such topics as the "Religious Aspects of Nazism" or "Adolf Hitler's Religious Beliefs" are mind-bogglingly complex, intractably tendentious, and incapable of any simple, straightforward summary. But this is not true.
(1) Adolf Hilter was a Christian, and the vast majority of Nazis were Christians.
(2) Anti-semitism and strident German nationalism were widespread among both Catholics and Protestants in Germany during the decades leading up to the Nazi seizure of power.
(3) Antisemitism had been a permanent and pervasive feature of European Christendom continuously throughout its history (inclusive of the Protestant late-comers).
(4) By the late 19th century anti-semitism was a core feature of political conservatism in Germany, and these same conservatives were overwhelmingly Christians who believed that Germany should be a "Christian State".
(5) Even those Nazis (such as Himmler) who are often referred to as "neo-paganists" were consistent, and insistent, admirers of Jesus and Luther (and also Meister Eckhardt). The hostility of these "neo-paganists" was primarily directed against Catholicism.
Below are some excerpts from Christoper R. Browning's 2004 The Origins of the Final Solution: The Evolution of Nazi Jewish Policy. These are all taken from the the first chapter of that book, which is titled, simply, Background. (I have provided some links and some comments inserted in brackets but I have refrained from adding any emphases to allow the original to speak for itself.)
Christians and Jews had lived in an adversarial relationship since the first century of the common era, when the early followers of Jesus failed to persuade significant numbers of their fellow Jews that he was the Messiah. They then gradually solidified their identity as a new religion rather than a reforming Jewish sect. First, Pauline Christianity took the step of seeking converts not just among Jews but also among the Pagan populations of the Roman Empire. [This is the one important thing that Browning gets wrong in this summary spanning two millennia of history: the Jews were already a proselytizing sect, and had been for centuries prior to Paul.] Second, the Gospel writers -- some 40 to 60 years after the death 0f Jesus -- sought to placate the Roman authorities and at the same time to stigmatize their rivals by increasingly portraying the Jews rather than the Roman authorities in Palestine as responsible for the crucifixion -- the scriptural origin of the fateful "Christ-killer" libel. Finally, the Jewish rebellion in Palestine and the destruction of the Second Temple motivated early Christians not only to dissociate themselves completely form the Jews but to see the Jewish catastrophe as a deserved punishment for the stubborn refusal to accept Jesus as teh Messiah and as a divine vindication of their own beliefs. Christians and Jews, two small sects that had much more in common with one another by virture of their monotheism and scriptures than either had with the rest of the tolerant, syncretic, polytheistic Pagan Roman world, developed an implacable hostility to one another.[Having taken us through more than one thousand years of the Jewish-Christian "adversarial relationship", Browning then proceeds to describe the further development of "xenophobic" anti-Semitism, which I will skip over. Then he comes to the second great "modernization crisis" which centered on the French Revolution and the Industrial Revolution, finally bringing us to the 19th century.]
This hostility became historically significant in the course of the fourth century when, following the conversion of the Emperor Constantine, Christianity became first the favored and then the official religion of the Roman Empire. The religious quarrel between two small and relatively powerless sects, both at odds with the Pagan world in which they lived, was suddenly transformed into an unequal relationship between a triumphant state religion and a beleaguered religious minority. Even so, the Jews fared better than the Pagans. Triumphant Christianity destroyed Paganism and tore down its temples, but the synagogues were left standing, and Judaism remained as the sole legally permitted religion outside Christianity. Without this double standard of intolerance -- Paganism destroyed and Judaism despised but permitted -- there would have been no further history of Christian-Jewish relations.
Seemingly triumphant Christianity soon faced its own centuries-long string of disasters. As demographic and economic declines eroded the strength of the Christianized Roman Empire from within, the western provinces fragmented and collapsed under the impact of the numerically rather small Germanic invasions from the north. The later invasion of the Huns from the east dissipated, but not so the subsequent Muslim invasions, which stormed out of the Arabian Peninsula and conquered half the old Roman world by the end of the seventh century. In the area destined to become western Europe, cities -- along with urban culture and a money economy -- illiterate, impoverished, and huddled in isolated villages scraping out a precarious living from a primitive subsistence agriculture -- reeled under the impact of yet further devastating invasions of Vikings form Scandinavia and Magyars from central Asia in the ninth and tenth centuries. Neither the Christian majority nor the Jewish minority of western Europe could find much solace in these centuries of afflication and decline.
The great recovery -- demographic, economic, cultural, and political -- began shortly before the milllennium. Population exploded, cities grew up, wealth multiplied, centralizing monarchies began to triumph over feudal anarchy, universities were invented, cultural treasures of the classical world were recovered and the borders of western Christendom began to expand.
But the great transformation did not bring equal benefits to all Europe's first great "modernization crisis," like any such profound transformation, had its "social losers." A surplus of disgruntled mounted warriors -- Europe's feudal elite -- faced constricted opportunities and outlets. A new money economy and urban society eroded traditional manorial relationships. Expanding literacy adn university education, coupled with an intoxicating discovery of Aristotelian rationalism, posed a potential and unsettling threat to traditional Christian faith. Growth, prosperity, and religious enthusiasm were accompanied by bewilderment, frustration and doubt.
For all that was new and unsettling, incomprehensible and threatening, in this modernizing crisis, the Jewish minority provided an apt symbol. The anti-Judaism (and "teaching of contempt") of Christian theologians that characterized the first millennium of Chrstian-Jewish antagonism was rapidly superseded by what Gavin Langmuir has called a "xenophobic" anti-Semitism -- a widely held negative stereotype made up of various assertions that did not describe the real Jewish minority but rather symbolized various threats and menaces that the Christian majority could not did not want to understand. A cluster of anti-Jewish incidents at the end of the first decade of the 11th century signaled a change that became more fully apparent with the murderous pogroms perpetrated by roving gangs of knights on their way to the First Crusade. In the words of Langmuir, "These groups seem to have been made up of people whose sense of identity had been seriously undermined by rapidly changing social conditions that they could not control or understand and to which they could not adapt successfully."
[I]n the far more secular and scientific world of the 19th century, religious beliefs provided less explanatory power. For many, Jewish behavior had to be understood instead as caused by allegedly immutable characteristics of the Jewish race. The implications of racial anti-Semitism posed a different kind of threat. If previously the Christian majority pressured Jews to convert and more recently to assimilate, racial anti-Semitism provided no behavioral escape. Jews as a race could not change their ancestors. They could only disappear.[Then Browning states that "These developments in the history of anti-Semitism transcended national boundaries and were pan-European." He follows that with the question: "Why then did the Germans, among the peoples of Europe, come to play such a fateful role in the murderous climax that was reached in the middle of the 20th century?" Browning then considers three different "approaches" to answering that question, most of which I will skip over. except for the following summary, which makes a good place to stop.]
If race rather than religion now provided the rationale for anti-Semitism, the various elements of the negative anti-Semite stereotype that had accumulated during the second half of the Middle Ages were taken over almost in their entirety and needed little updating. The only significant addition was the accusation that Jews were responsible for the threat of Marxist revolution. With little regard for logical consistency, the old negative image of Jews as parasitical usurers (updated as rapacious capitalists) was supplemented with a new image of Jews as subversive revolutionaries out to destroy private property and capitalism and overturn the social order. After 1917 the notion of menacing "Judeo-Bolshevism" became as entrenched among Europe's conservatives as the notion of "Christ-killers" had been among Europe's Christians.
Shulamit Volkov's interpretation of late 19th century German anti-Semitism as a "cultural code" constitutes an admirable synthesis of major elements of these different, though not mutually exclusive, notions of a German Sonderweg. German conservatives, dominating an illiberal political system but feeling their leading role increasingly imperiled by changes unleashed by modernization, associated Jews with everything they felt threatened by -- liberalism, democracy, socialism, internationalism, capitalism, and cultural experimentation. To be a self-proclaimed anti-Semite in Germany was also to be authoritarian, nationalist, imperialist, protectionist, corporative, and culturally traditional. Volkov concludes, "Antisemitism was by then strongly associated with everything the conservatives stood for. It became increasingly inseparable from their anti-modernism." As Uriel Tal has noted, German conservatives made their peace with modern nationalism and the modern state by understanding them in terms of a traditional German "Christian state" and traditional values that were seen as the distinct antithesis of the values identified with modern, emancipated, relatively assimilated Jews.The next installment in this series will focus on Richard Steigmann-Gall's book Holy Reich: Nazi Conceptions of Christianity 1919-1945.
The series on "Nazis & Christians & Pagans":
 Nazis and Christians and Pagans, Oh My! (Part One)
 Christian Nazi Quote-fest (Part Two)
 Fascism, Islam, and Freedom of Expression (Part Three)
 "Hitler was not an occultist": Mitch Horowitz is right but his sourcing is all wrong (Part Four)
 Karla Poewe's "New Religions and the Nazis" reviewed by Richard Steigmann-Gall (Part Five)
 Rosenberg, Chamberlain, Harnack (Part Six)
Much of the history that Christopher R. Browning covers in the above excerpts is also discussed in a series of posts I have done on the History of Monotheism:
Charlemagne, Part Deux (A Brief History of Revolutionary Monotheism, Part Six)
Charlemagne (A Brief History of Revolutionary Monotheism, Part Five)
Muhammad (A brief history of Revolutionary Monotheism, Part Four)
Constantine (A brief history of Revolutionary Monotheism, Part Three)
Moses (A Brief History of Revolutionary Monotheism, Part Two)
Akhenaten (A Brief History of Revolutionary Monotheism, Part One)
Monotheistic Robots of Doom, Part Deux
Monotheistic Robots of Doom