In his preface, Nietzsche anticipates a likely backlash, stating that only those of sound intellect, above the "wretched gabble of politics and national egotism," will understand his words. Plainly put, this publication won't be well-received by all.
Nietzsche argues that Christianity has sided with the weak and botched, corrupting even the strongest intellects. He defines "faith" as blind ignorance of truth and reason.
In Nietzsche's view, Christianity is completely detached from reality, its validity supported by imaginary effects, causes, beings, and psychology. Sin, salvation, and other such concepts are tools of a nefarious trade.
The keys to controlling Christian congregations, according to Nietzsche, are "guilt" and "sin." Without them, Christianity is impotent. It's not about actual sin, but the feeling of sin that keeps the priest employed and the flock in line.
Surprisingly, Nietzsche has a soft spot for Christ, calling him the "only true Christian" and comparing him favorably to Buddha. However, he blames St Paul for bastardizing the Christian identity, seeing him as the incarnation of hatred and a seeker of power.
Overall, Nietzsche's take on Christianity is a collection of valid points and questionable conjectures, cynical, eristic, and inflammatory. Five stars!