The history of Christianity is fascinating, partly because the imposition of Christianity had such a devastating effect upon Western Culture, but also because the historical facts have a devastating effect on Christian beliefs.
What came to be accepted as Christianity was largely influenced by Paul; he set the tone. Unfortunately, Paul was apparently quite neurotic, self-conscious, uneasy with himself, celibate, and jealous of other opinions.
In addition, what became Christianity was also the product of in-fighting, imperial fiat, committee decisions, language differences, other religions, and a huge portion of sheer imagination.
If, as many scholars will agree, Christianity as we know it began with Paul, then that is further evidence for the following: From the beginning, Christianity was intolerant and exclusive of other religions. It was anti-intellectual. It was both fascinated and repulsed by sex. It was not based on any direct knowledge of, or experience with, Jesus. From the beginning, it was developed ad hoc, out of whole cloth, in response to external events, personal feelings, and differing opinions.
By the time Christianity had coalesced into near-orthodoxy, it had taken an anti-establishment, peace-loving human, living in simplicity, and elevated him to an imperial, warlike god, living in splendor. It had created, modified, or suppressed various scriptures to support its ideas, developed other ideas without any supporting evidence, and devised still others in direct contradiction to existing evidence and scriptures.
Because of this history, we can have no confidence whatsoever that Christian beliefs represent truths or have coherence of any kind.
The best argument against Christian beliefs is not about contradictions in the scriptures; they have no basis in fact. It is not based on logical arguments about religious tenets; they have no coherence or axiomatic value. The best argument against Christian beliefs is the history of those beliefs!
For a philosophical view of the history of Christianity, see Book Two of Bertrand Russell’s A History of Western Philosophy. For a theological history, see Charles Freeman’s The Closing of the Western Mind. For detailed, scholarly, and readable analyses of Christian scriptures, read books by Bart Ehrman. If, like most Christians, you don’t know this history, you will be amazed.