In my experience as a minister, I have found people abandon their faith for one of three reasons: First, because they have experienced some tremendous personal tragedy and feel that God has let them down. Second, they encounter intellectual challenges which cause them to question what they have been taught about God. Not being able to harmonize the two, they abandon faith for what they perceive as greater truth. Third, people abandon faith because it allows them the freedom to live as they please without worrying about giving an account for their behavior.
The last of these is most often the motivation for the loss of faith, but the first two are the reasons most usually given. In other words, people lie.
The second of these is the result of a premature conclusion: not having all the facts. There are no intellectual arguments damning to the Bible story nor the God who created it. There are just protestations that have not been carefully thought through.
The first of these is really, the best argument for abandoning faith. If God knew what was going on in my life, loved me, and was powerful enough to rescue me, He would. But he hasn’t, so either he doesn’t love me (in which case why should I love Him) or he can’t save me (in which case He isn’t much of a God).
The writer of the book of Hebrews offers, in chapter eleven, a list of people who had every reason to give up faith. But they didn’t. And they reason they didn’t was that they were confident in what they believed – even if it didn’t match what they saw. Only in faith could they find hope.
We don’t embrace faith without foundation just so we can have an imagined hope. God never calls us to that. It’s why He has always acted first – to provide proof for His reliability. Because He can be trusted, we trust, and never give up, for the alternative is an empty and hollow life not worth remembering.