If one aspired to be an expert on counterfeit currency, the first stage would not be to study hundreds of fake banknotes, but to know really well what a good one looks like.
In the same way, I think the most important thing that Bible-believing Christians should do is not so much to keep inveighing against false doctrine (though I'm sure there is a place for that), but to concentrate on preaching the true. This is Paul's advice in Ephesians 4:11-16 & 2 Timothy 4:1-5. If Christians get to know true doctrines really well, they won't fall for phoney teaching
In the same way, I think the most important thing that Bible-believing Christians should do is not so much to keep inveighing against false doctrine (though I'm sure there is a place for that), but to concentrate on preaching the true. This is Paul's advice in Ephesians 4:11-16 & 2 Timothy 4:1-5. If Christians get to know true doctrines really well, they won't fall for phoney teaching