With that in mind, the question we are asking today might be stated as follows:
What are the marks of cult groups and apostate forms of Christianity that identify them as false religions—such that we can and should label them as heresies, rather than simply classifying them as different denominations?
Here is my attempt to answer that question in 200 words or less:
The New Testament articulates three fundamental doctrinal criteria by which false teachers (and false religions) can be identified:
1. A Wrong View of Salvation
False religions (whether they claim to be Christian or not) attempt to add good works to the gospel of grace (cf. Rom. 11:6). Rather than trusting in Christ alone for salvation, they seek to earn God’s favor through self-righteous works and human effort (cf. Acts 15:1–11; Gal. 1:6–9; Eph. 2:8–9; Php. 3:8–9; Titus 3:5–7).
2. A Wrong View of Scripture
False teachers distort, deny, and deliberately disobey the Scriptures (2 Pet. 2:1, 3:16). They add to or subtract from God’s revealed truth (cf. John 17:17; Rev. 22:18–19), looking to some other false authority for their beliefs (Mark 7:6–12; cf. 2 Cor. 10:5).
3. A Wrong View of the Savior
False religions twist the truth about Jesus Christ. They deny aspects of either His Person (e.g. His deity, humanity, eternality, uniqueness, etc.) or His work (e.g. His death, resurrection, ascension, etc.). Those who do not worship the true Christ are not truly Christian (John 4:24; cf. John 1:1, 14; 1 John 1:1; 2:22–23; 4:1–3; 2 John 7–11).