What is the doctrine of Christ according to the Bible?

The doctrine of Christ is of utmost importance in the Reformed faith and is outlined in 2 John 1:9, which states that 'whosoever transgresseth and abideth not in the doctrine of Christ hath not God.' This teaching asserts that any theological discourse or belief system that deviates from the truth of Christ constitutes false doctrine. As Christians, it is critical to align our beliefs solely around Jesus, recognizing Him as the only source of righteousness, the fulfillment of the law, and the embodiment of truth. Any addition to the doctrine of Christ is viewed as a heretical departure from the gospel, emphasizing that salvation is found solely in Him.