Why is the doctrine of Christ important for Christians?

The doctrine of Christ is crucial for Christians because it encapsulates the truth of who Jesus is and what He accomplished for humanity. According to 2 John 9, those who do not abide in the doctrine of Christ cannot claim to have God. This indicates that the nature and teachings of Christ are foundational to our faith. Without acknowledging Christ as both fully God and fully man, and without recognizing His redemptive work, one cannot rightly relate to God. Christians must hold firmly to this doctrine to experience the fullness of joy and fellowship with the Father and the Son, as ultimately, our salvation, hope, and life hinge on the truth of the gospel centered around Christ.