(2 John 9-11)
The aged Apostle John, writing to the unknown " elect lady and her children," gave a very solemn warning as to departing from " the doctrine of Christ." We quote his words, "Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son. If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: for he that biddeth him God speed is partaker of his evil deeds." (2 John 9-11).
In a letter addressed to a lady and her children, one would not expect that anything of assembly discipline would be mentioned. But if they were exhorted to shut their door against any, who brought not the doctrine of Christ, and were warned, that to bid such God speed would make them partakers of his evil deeds, surely it would be necessary, if such cases occurred in any Christian assembly, to excommunicate the offenders, after every effort, to show them the seriousness of their teaching, had failed.
And note, it would not have sufficed for those, who brought not the doctrine of Christ, to say that they neither affirmed nor denied that doctrine, for the Scripture plainly says, " If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed." This specious middle course of neither affirming nor denying, when teaching plainly contrary to the doctrine of Christ is in question, would leave the door open to the possibility of evil being spread secretly among the Lord's people with disastrous consequences. Hence the utmost diligence is demanded.
When once a body of believers cannot or will not be vigilant in this matter, it would mean the end of their true testimony to the Lord.