Why heresy matters

I’m sure this is probably not an original thought, but I’ve been wondering about heresy lately and I think I’ve noticed something important about it. Specifically, I’ve been wondering why there’s an apparent distinction between the OT and the NT, in that the former does not seem to discuss false doctrine much (except by implication), at least in comparison to the NT. Why is that?

I think the answer is basically this: false doctrine, the kind that destroys souls, is a form of idolatry. I know theologians of various types have made this point before, but I’ve just recently recognized that the apostles themselves made this kind of connection. For example, three major heresies addressed in the epistles are: the Galatian heresy, a sort of proto-Docetic heresy, and a denial of the resurrection. In all three cases, however, something interesting appears.

With regard to the first:

Gal 4:6-9: And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So you are no longer a slave, but a son, and if a son, then an heir through God. Formerly, when you did not know God, you were enslaved to those that by nature are not gods. But now that you have come to know God, or rather to be known by God, how can you turn back again to the weak and worthless elementary principles of the world, whose slaves you want to be once more?

Here Paul seems to suggest that idolatry is inherent in the Galatian heresy. Similarly, John closes his first letter, containing warnings against denying Christ in the flesh, with this line:

1Jn 5:21: Little children, keep yourselves from idols.

Assuming John was not randomly changing the subject with this closing words, the probable logical connection between this warning and the rest of the letter is that denying Christ came in the flesh is actually a kind of idolatry.

Similarly, with regard to denying the resurrection, Paul warns the Corinthians with these words:

1 Cor 15:33-34: Do not be deceived: “Bad company ruins good morals.” Wake up from your drunken stupor, as is right, and do not go on sinning. For some have no knowledge of God. I say this to your shame.

The phrase “have no knowledge of God” would suggest that Paul thinks this heresy has seeped into the church from the outside, because the Corinthians are associating too much with idolaters who do not know the true God. So, this heresy is also rooted in some sort of idolatry.

What this suggests to me is that the vehemence with which the apostles condemned some false doctrines is not something very different from the OT. Rather, just as the OT prophets condemned idolatry as the sin above all sins, so the apostles condemn certain false doctrines with equal vigour, because they are in fact the same sin.

Or at least, so it seems to me.

If I am anything close to correct, it would also seem that that the post-apostolic church was right to condemn theological and christological heresies as putting heretics outside of the pale. In doing this, they were simply following apostolic logic. Ultimately, the main thing that unites the church is not a doctrine or body of doctrines, but a single God.