This sets the stage for a sober warning, which stands for all of God’s people in every generation.  We are ever to be looking to ourselves, guarding ourselves, not only personally, but also corporately, as bodies of believers.  We may have wrought much in the kingdom of Christ, but all those good things will profit us nothing if we turn our backs on Him now to pursue false doctrine.  It is not those who start out on the road and travel part of the way who reach their destination, but those who persevere unto the end.  If we desire to receive any reward from God for those things which we have done in His service up till now, we must continue in His service, maintaining purity of faith and doctrine, and never letting it go until the Lord discharges the battle by death.  Only those who overcome by the blood of the Lamb and by the word of their testimony will receive a full reward.


In the context, I think John is specifically urging us to maintain the true doctrine of the person of Christ, and to continue walking in love towards Him and to one another, in order that we receive a full reward for the things we have wrought; a reward, of course, that is reckoned of grace, and not of debt.