Why is abiding in the doctrine of Christ important for Christians?

Abiding in the doctrine of Christ is essential for true believers because it solidifies their relationship with God. As stated in 2 John 9, only those who abide in this doctrine can claim to have God. This abiding signifies a continuing faith in the truth of who Christ is and what He has accomplished. It involves understanding and embracing His work of redemption, which ensures that believers are grounded in the faith and not swayed by false doctrines. Moreover, it affirms our status as children of God and provides assurance of eternal life, as found in 1 John 5:11-12.