Verse 11. - To give countenance and sanction to false doctrine is to share in the responsibility for all the harm which such false doctrine does. With which solemn warning the main portion of the Epistle ends.

1:7-11 The deceiver and his deceit are described: he brings some error concerning the person or office of the Lord Jesus. Such a one is a deceiver and an antichrist; he deludes souls, and undermines the glory and kingdom of the Lord Christ. Let us not think it strange, that there are deceivers and opposers of the Lord Christ's name and dignity now, for there were such, even in the apostles' times. The more deceivers and deceits abound, the more watchful the disciples must be. Sad it is, that splendid attainments in the school of Christ, should ever be lost. The way to gain the full reward is, to abide true to Christ, and constant in religion to the end. Firm cleaving to Christian truth unites us to Christ, and thereby to the Father also; for they are one. Let us equally disregard such as abide not in the doctrine of Christ, and those who transgress his commands. Any who did not profess and preach the doctrine of Christ, respecting him as the Son of God, and salvation by him from guilt and sin, were not to be noticed and countenanced. Yet in obeying this command, we must show kindness and a good spirit to those who differ from us in lesser matters, but hold firmly the all-important doctrines of Christ's person, atonement, and holy salvation.For he that biddeth him God speed,.... Wishes him well, and success in his ministry, or in a friendly and familiar way converses with him:

is partaker of his evil deeds; he has fellowship with him, instead of reproving or shunning him, as he ought; he is an abettor of him in his principles, and so far joins in the propagation of them, and helps to spread them, and gives too much reason to think he is one with him in them.