How can even a slight deviation from the biblical teaching of the person and/or work of Christ harm a person’s life?
If Christ is not God and if his atoning work was not actually finished on the cross, then some created being will have to compensate for the insufficiency of Christ’s work. That could be oneself or some sort of priest or prophet.
Regardless of the identity of the additional savior, a consequence of that pursuit is that someone, again whether oneself or another created being, will end up being trusted in, even if it’s just for a part of one’s salvation. And because there is trust put forth in another object outside of Christ, that object is worshipped, either alongside Christ or instead of Christ.
Clearly, the first monumental problem with that is idolatry, while stealing glory from God. Secondly, there’s no power in such things, but only empty deception. In other words, there can be no true spiritual life in Christ when something or someone is added next to Christ as a source of one’s spiritual life. If that is not fought against, confidence in a full and complete salvation in Christ is increasingly reduced and perhaps gradually eliminated altogether. This is why Paul writes in Colossians 1:21 And although you were formerly alienated and hostile in mind, engaged in evil deeds, 22 yet He has now reconciled you in His fleshly body through death, in order to present you before Him holy and blameless and beyond reproach— 23 if indeed you continue in the faith firmly established and steadfast, and not moved away from the hope of the gospel that you have heard, which was proclaimed in all creation under heaven, and of which I, Paul, was made a minister.
Adding to Christ’s work is turning from Christ
