Why should Christians reject teachings that contradict the doctrine of Christ?

The rejection of teachings that contradict the doctrine of Christ is crucial for maintaining the purity of the Christian faith. As mentioned in 2 John 9, anyone who comes teaching a different doctrine should not be welcomed, as they are partaking in evil deeds by misleading others. Accepting or endorsing these teachings can lead to confusion and compromise of the true gospel, which is centered on Jesus Christ and His work. By standing firmly against such teachings, Christians safeguard their own beliefs and the integrity of their witness to others, ensuring that the truth of Christ remains at the core of their congregational life and personal faith.