Probably the biggest faith part is being able to accept that something like the Christian story of Jesus could even be possible in the first place.
I think that the path from Christianity to Atheism requires a similar leap of faith. A person has to start out by accepting
the possibility that there is no God and that the Bible was simply written by men.
Instead, most Christians look at the Bible and think to themselves: Can I have faith in this? They are already so culturally conditioned to accept belief in the Bible as legitimate, that they don't really subject it to the same level of skepticism they would apply to other texts, like the Qu'ran or the Book of Mormon.
I would invite all the Christians reading this to take a step back and consider things from an abstract perspective. Instead of analyzing whether the Bible is true, let's consider the legitimacy of a hypothetical religious text. What attributes would we expect if the book was divinely inspired? What potential signs might make us suspect that it was written by ancient men without God's help?
IF DIVINE
On the most basic level, the two attributes we would expect of a divine text are: (1) Moral Consistency; and (2) Scientific Accuracy.
1. We expect the book to be consistent, because it purports to contain the word of an eternal God. Obviously, if it's going to be transcribed by men, there might be some minor anomalies. But the primary doctrine should remain constant throughout, because it's really coming from God. God invented morality, so we should see him consistently applying his moral rules, right?
2. We expect the book to be accurate, because God knows everything about the Universe that he created. If he is explaining that Universe to humans, then he shouldn't make mistakes when he describes it. And if he is bothering to explain it to humans, he probably will cover the most basic aspects of things like how he created animals or what's out there in the rest of the giant cosmos he built. He might use terms that ancient people could understand, but the substance of what he says should be accurate. The more that science discovers about the Universe, the more it should confirm the information in this book from God.
IF NOT DIVINE
If the book was written by ancient men without help from God, we would expect exactly the opposite. It will likely be: (1) Morally Inconsistent; and (2) Scientifically Inaccurate.
1. If the book was written without God, then it will be morally inconsistent because throughout history human morals have constantly been in flux. We would expect the human authors to apply the prevailing moral standards of their time, and those standards will progressively change. The authors don't have any actual revealed truths from God to rely on, so there won't be a consistent logic to the morality that the book describes. The biggest differences will probably be between the oldest and newest parts, because in the time between them morality would have had the most time to be transformed by social progress.
2. If the book was written without God, then it will only reflect the state of scientific knowledge that was available to the ancient human authors. God will not be revealing any actual divine truths to these men, so they will probably make assumptions about the universe that later generations are able to disprove. Science will make discoveries that outright contradict the substantive claims of the text, just like it disproves the ideas of so many ancient thinkers.
WHICH IS THE BIBLE?
I won't go into great detail here, because everybody can consider this question for themselves. But in my opinion, the two glaring weaknesses in the bible are: (1) the extreme change in morality between the Old and New Testament; and (2) God's failure to disclose that he made us from animals. To me, those are huge red flags.
