In Gospel Disproof #28 we looked at conditional salvation and how bizarre it was to suppose that a loving and self-sufficient Father would create a situation where His beloved children would go to Hell forever unless they met certain rarely-obtained conditions. As a parenting scenario, it just doesn’t work, but by an odd coincidence it works great as a tool for manipulating people and making them think that they have to submit to you and your teachings in order to be saved.
Salvation by faith takes that manipulation one step further: not only does your salvation depend on submitting to some human teacher, but you have to believe that what he tells you is absolutely and infallibly true. It’s not enough to merely try to be good or to behave in ways that make you an asset to the community. You have to believe, even when it makes no sense, and even when it’s in conflict with what you see around you.