How do we listen to heretical sermons? The short answer is: DON’T!
The longer answer requires some attention. If you’re in a church currently that goes against historical doctrine of the Christian Church, a few things need to be considered.
First, is the error something central to the Christian faith or something peripheral? Someone is not a heretic if they are wrong on their view of the millennium (whatever you may think wrong may be in this case.) Someone is not a heretic if they are wrong on the nature of church government, or the proper age and mode of baptism. On the other hand, they are a heretic if they deny Jesus is both 100% God and 100% man. That salvation is by faith not works. If they call good evil and evil good. If they deny the trinity. Basically, they are a heretic if they deny anything in the Apostles Creed.
Second, a person is not a heretic when they get something wrong and then put it right when they are corrected. This shows a teachable, humble spirit, one you want in a pastor. They are heretics, however, if they continue to hold and teach their position after being shown clearly that they are in the wrong by numerous people. This reveals the person is not only in the wrong about central doctrine, but that they have an unteachable spirit, which is not a quality suitable for an elder, especially an elder who teaches.
Third, a person is a heretic when they try to teach their heresy. Private opinions do not make heretics. Mistakes do not make heretics. The word heretic is reserved for a certain kind of person in the Bible, the false teacher. God does not like false teachers, because He is dishonored and man is hurt. Sure, wrong beliefs held personally and quietly may endanger someone’s soul, but the false teacher endangers their own soul and all the souls listening if they seek to publicly teach their heresy.
So what do you do if you find consistent heresy in preaching? It is plain and clear, painful but necessary. Leave the church, and seek out a church that is one thing: faithful to Scripture.
(Adapted from LISTEN UP! Christopher Ash, 2009)