I grew up going to church but I’m not religious now and I never really understood this part.
Please, no answers along the lines of “aha, that’s why Christianity is a sham” or “religions aren’t logical”. I don’t want to debate whether it’s right or wrong, I just want to understand the logic and reasoning that Christians use to explain this.
It varies significantly between denominations, I know that much. Guaranteed salvation is protestant-specific, at the very least, and isn’t even held by all denominations within.