1 John 2:19

1 John 2:19. This verse stands alone, as containing a preliminary encouragement. They went out from us, but they were not of us. They literally left us, for they were in our fellowship, and received in the Church the doctrines they perverted; but they had not the life of our doctrine, and were not of us in the sense of that fellowship of which the first chapter had spoken. For if they had been of us, in this latter sense, they would have continued with us, in the former sense. But the apostle is hurrying from them and hurries them away, in an elliptical sentence, ‘this came to pass'

that they might be made manifest that they are not all of us. The consequence is a purpose: they have gone according to the fixed purpose of God's Spirit that heresy should be purged out of the Church. It is true that by their going out they show the possibility of some being ‘with us' who are not ‘of us.' But the words, which are not so involved in the original as many think, do not say this. They only declare that such heresy cannot and must not continue in the Christian fellowship, continue, that is, as maintained by teachers: as members of the fellowship all need the subsequent exhortation to ‘abide in Him,' and the warning against being ‘ashamed before Him at His coming. The reason of the necessary rejection of heresy is given in the next verse.