According to the Bible, heretics are people who claim to believe in God but do not keep God’s commands, being tempted by man-made rules and theories (2 Pe 2:1–3).
Whether a belief is heresy or not can be determined by whether it is following the commands of Jesus Christ.
In the days of the early Church, too, there was a warning against heresies (Tit 3:10). Since then, paganism entered the church and settled down as if it were authentic Christian services. In the process, theories and creeds against the Bible took the form of Christian doctrines and have been observed up until now.
In this sense, the Bible points out that today’s churches that do not keep God’s commandments while claiming to believe in God are following heresies.
The Church of God is the only true church that obeys God’s commandments and holds to the testimony of Jesus (Rev 14:12).