Nuggets from "An Urgent Call to a Serious Faith" by Dave Hunt - How Important Is Doctrine?

The sufficiency and importance of biblical truth and doctrine are presented powerfully in John’s brief second epistle. John mentions truth five times in the first four verses. He then warns about deceivers who pose as Christians but who deny the doctrine of Christ. Showing how essential sound doctrine is, he declares that anyone who “abideth not in the doctrine of Christ has not God” (verse 9). He then commands separation from such persons. How important, then, is the current battle being waged for sound doctrine!

Most of the epistles were written to correct doctrinal error. Doctrinal purity is essential not only for salvation but also for living the Christian life. Paul wrote to Timothy, “Thou has fully known my doctrine, manner of life, purpose, faith, longsuffering, charity, patience, persecutions, afflictions…” (2 Timothy:3:10-11 [10] But thou hast fully known my doctrine, manner of life, purpose, faith, longsuffering, charity, patience, [11] Persecutions, afflictions, which came unto me at Antioch, at Iconium, at Lystra; what persecutions I endured: but out of them all the Lord delivered me.
See All...). Doctrine was the very foundation of Paul’s life. And so it must be of ours.

Universalisms, such as “anyone can worship God in his own way,” are condemned by John’s statement that “Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God” (2 John 9). Why? Because Christ said, “I am the way, the truth, and the life: no man cometh to the Father, but by me” (John:14:6Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
See All...). This statement is foundational to the “doctrine of Christ” that John says separates true Christians from the rest of the world. In defense of that doctrine, millions have died as martyrs of the faith.