5 And ye know that he was manifested, or, hath appeared. He shews by another argument how much sin and faith differ from one another; for it is the office of Christ to take away sins, and for this end was he sent by the Father; and it is by faith we partake of Christ’s virtue. Then he who believes in Christ is necessarily cleansed from his sins. But it is said in John 1:29, that Christ takes away sins, because he atoned for them by the sacrifice of his death, that they may not be imputed to us before God: John means in this place that Christ really, and, so to speak, actually takes away sins, because through him our old man is crucified, and his Spirit, by means of repentance, mortifies the flesh with all its lusts. For the context does not allow us to explain this of the remission of sins; for, as I have said, he thus reasons, “They who cease not to sin, render void the benefits derived from Christ, since he came to destroy the reigning power of sin.” This belongs to the sanctification of the Spirit.
And in him is no sin He does not speak of Christ personally, but of his whole body. (78) Wherever Christ diffuses his efficacious grace, he denies that there is any more room for sin. He, therefore, immediately draws this inference, that they sin not who remain in Christ. For if he dwells in us by faith, he performs his own work, that is, he cleanses us from sins. It hence appears what it is to sin For Christ by his Spirit does not perfectly renew us at once, or in an instant, but he continues our renovation throughout life. It cannot then be but that the faithful are exposed to sin as long as they live in the world; but as far as the kingdom of Christ prevails in them, sin is abolished. In the meantime they are designated according to the prevailing principle, that is, they are said to be righteous and to live righteously, because they sincerely aspire to righteousness.
They are said not to sin, because they consent not to sin, though they labor under the infirmity of the flesh; but, on the contrary, they struggle with groaning, so that they can truly testify with Paul that they do the evil they would not.
He says that the faithful abide in Christ, because we are by faith united to him, and made one with him.
(78) It is generally taken as referring to Christ personally; he being mentioned here as having no sin, because he is in this respect an example to his people; or, according to some, because he was thereby fitted for the office of taking away our sins; or, because he had no sin of his own to take away. Grotius viewed the present as used here for the past tense, — “and sin was not in him.” See a similar instance in John 15:27 — Ed.