As a teenager I attended a high school Bible club. It was evenly divided between Calvinists (those who teach that you sin every day and that it frustrates the grace of God for anyone to try to stop sinning) and non-Calvinists (called Armenians).
Once a week we would meet and exchange Bible verses to support our opposing views. And once a week we would go back to our pastors to get new verses to refute the ones offered by the others. To my knowledge, no one was ever converted in either direction, because no one was really listening.
This is the depressing picture of much that passes for Christianity. Rather than search for ultimate Truth, various factions search only for proof texts to support their particular brands of truth, which they then seek to preserve in isolation from any arguments to the contrary. This isolationist approach forces each group to shield their followers from hearing what the others are saying.
There is a sacred "ethic" amongst the various denominations that you must never invade another group with teachings that might question what is being offered there. Each would secretly like to convert the others; but they fear the same tactics being used on them if they should break the rule. Because neither side has a strong enough case to survive such an open forum, they agree mutually not to seek open debate.
With such an arrangement, each group can, in isolation from any statement to the contrary, present "convincing arguments" for their pet doctrines, even though the arguments tend to fall apart if other viewpoints are tolerated.
And sadly, even within a single denomination, a similar sort of tunnel vision stops people from comparing one teaching with another.
While arguing in favour of grace, for example, a Calvinist will insist that you can do just about anything and still get to heaven. But they contradict it with a number of theological "sins" for which people can be exempted from God's grace.
Working for employers and obeying the laws of the land are absolute requirements in most churches, while obeying the teachings of Jesus is condemned as trying to "work your way to heaven." The contradictions go on and on.
Until people make the effort to line one argument up with another, and arrive at truths which are consistent from every angle, they will never arrive at anything more than piecemeal arguments and justifications for whatever happens to be expedient at the time. One brick will not line up with another, and their "house" will not even have a recognisable wall, much less meaningful floor plans.
(See also
The Emperors New Clothes.)
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