When talking to some Mormon missionaries in March I encountered an interesting line of thinking. One of the elders gave the standard claim that the Bible is missing books that should have been included.
I asked, “Which ones?”
He answered: Works that the Bible makes mention of.
So I asked, “So, mere mention of a work in scripture (of something presumably written by another prophet) indicates that the work should have been included in the canon as scripture?”
They answered, “Yes, because what prophets write should be considered scripture.”
This later was downgraded to a more modest claim: That the majority of what prophets write for public consumption should be considered scripture.
This is the default, functioning, practical view of mainstream Mormonism:
“We believe all that God has revealed, all that He does now reveal, and we believe that He will yet reveal many great and important things pertaining to the Kingdom of God.” (Article #9)
This is “functionally” (in practice) taken to encompass most of what the LDS Church teaches and publishes, especially General Conference messages. I call this approach prima ecclesia. (It is far different than the standard LDS apologetic approach, which is something akin to sola scriptura.)
Just to dig this in, I asked: “Would you agree that prophets should be held to a high standard of expectation and accountability over what they publicly teach about God and the gospel?”
They answered, “Yes.”
These kinds of principles are important to pull out and explicate. Get them on the table. Help your Mormon neighbor commit to these principles — out loud. With words they commit to. This might seem simple but it’s radical. It implicitly presses the point that prophets should not be given a free pass for false teachings — especially and most obviously for public false teachings about God and the gospel which are never repented of.
The more clear and heavy you make the point, the more powerful things like Adam-God and the priesthood ban are. Jesus said to inspect alleged prophets by their fruits (Matthew 7:15-20). Serious fruit-inspection is a way of obeying Jesus. We’re also helping Mormons obey their own scripture: to study things out in their mind instead of depending on mere emotional epiphanies (D&C 9:7-8). I love what my friend Matt says about fruit-inspection: “Don’t do it with binoculars.” Peel the skin off and get dirty. It’s our responsibility.