Strictly for original context , here was the full quote. " But it remained for the Jews, with their unqualified capacity for falsehood, and their fighting comrades, the Marxists, to impute responsibility for the downfall precisely to the man who alone had shown a superhuman will and energy in his effort to prevent the catastrophe which he had foreseen and to save the nation from that hour of complete overthrow and shame. By placing responsibility for the loss of the world war on the shoulders of Ludendorff they took away the weapon of moral right from the only adversary dangerous enough to be likely to succeed in bringing the betrayers of the Fatherland to Justice.

All this was inspired by the principle—which is quite true within itself—that in the big lie there is always a certain force of credibility; because the broad masses of a nation are always more easily corrupted in the deeper strata of their emotional nature than consciously or voluntarily; and thus in the primitive simplicity of their minds they more readily fall victims to the big lie than the small lie, since they themselves often tell small lies in little matters but would be ashamed to resort to large-scale falsehoods.

It would never come into their heads to fabricate colossal untruths, and they would not believe that others could have the impudence to distort the truth so infamously. Even though the facts which prove this to be so may be brought clearly to their minds, they will still doubt and waver and will continue to think that there may be some other explanation. For the grossly impudent lie always leaves traces behind it, even after it has been nailed down, a fact which is known to all expert liars in this world and to all who conspire together in the art of lying. These people know only too well how to use falsehood for the basest purposes.

From time immemorial. however, the Jews have known better than any others how falsehood and calumny can be exploited. Is not their very existence founded on one great lie, namely, that they are a religious community, whereas in reality they are a race? And what a race! One of the greatest thinkers that mankind has produced has branded the Jews for all time with a statement which is profoundly and exactly true. He (Schopenhauer) called the Jew "The Great Master of Lies". Those who do not realize the truth of that statement, or do not wish to believe it, will never be able to lend a hand in helping Truth to prevail. " [en.m.wikipedia.org]

By way of agreeing with your excerpt, "a certain force of credibility" appears to appeal first and foremost to people's emotions and only secondarily to "intellect," such as it is. I have just been reading Robert Wright's "Why Buddhism is True: the Science and Philosophy of Meditation and Enlightenment." Wright is a psychologist who has examined some neuro-psychological research as it applies to consciousness, human identity/perception of self, and has applied findings to the Buddhist concept of individual, singular, consciousness being something of an illusion we experience, that our minds actually appear to be comprised of numerous varied perspectives, value priorities, and preferences and that rather than us having a single executive "self" applying reason to make our choices, we actually appear to be ruled by several competing decision-making faculties. According to Wright, which one bubbles up to the level of conscious awareness at any given moment will be the one likely to execute a decision at the moment, and it appears that emotions seem to be far more powerful than reason in determining that "bubbling up ." Another way of saying it is, despite believing we are essentially rational , we are in fact essentially ruled by emotions, and our powers of reason serve to try to advise those emotions to strategize how best to satisfy them and then to rationalize to ourselves plausible sounding excuses for our decisions, but reason is never the ruling executive power; emotion is.

This can explain how an absolutely reprehensible conman like Trump keeps duping people, even some who, in other aspects of their lives seem capable and reasonably intelligent. They don't even consider the facts of his rampant lying when it is pointed out to them because the facts in question are not as important to them as their gut level negative feelings about immigrants, race minorities, educated "elites," LGBT people, "scary liberals," "feminists," "tree-huggers," and/or the experience that other people seem to benefit more from the economy than they themselves do.