Here, I. The apostle, having supposed that even those of this heavenly communion have yet their sin, proceeds here to justify that supposition, and this he does by showing the dreadful consequences of denying it, and that in two particulars:—1. If we say, We have no sin, we deceive ourselves, and the truth is not in us, 1 John 1:8. We must beware of deceiving ourselves in denying or excusing our sins. The more we see them the more we shall esteem and value the remedy. If we deny them, the truth is not in us, either the truth that is contrary to such denial (we lie in denying our sin), or the truth of religion, is not in us. The Christian religion is the religion of sinners, of such as have sinned, and in whom sin in some measure still dwells. The Christian life is a life of continued repentance, humiliation for and mortification of sin, of continual faith in, thankfulness for, and love to the Redeemer, and hopeful joyful expectation of a day of glorious redemption, in which the believer shall be fully and finally acquitted, and sin abolished for ever. 2. If we say, We have not sinned, we make him a liar, and his word is not in us, 1 John 1:10. The denial of our sin not only deceives ourselves, but reflects dishonour upon God. It challenges his veracity. He has abundantly testified of, and testified against, the sin of the world. And the Lord said in his heart (determined thus with himself), I will not again curse the ground (as he had then lately done) for man’s sake; for (or, with the learned bishop Patrick, though) the imagination of man’s heart is evil from his youth, Gen. 8:21. But God has given his testimony to the continued sin and sinfulness of the world, by providing a sufficient effectual sacrifice for sin, that will be needed in all ages, and to the continued sinfulness of believers themselves by requiring them continually to confess their sins, and apply themselves by faith to the blood of that sacrifice. And therefore, if we say either that we have not sinned or do not yet sin, the word of God is not in us, neither in our minds, as to the acquaintance we should have with it, nor in our hearts, as to the practical influence it should have upon us.
II. The apostle then instructs the believer in the way to the continued pardon of his sin. Here we have, 1. His duty in order thereto: If we confess our sins, 1 John 1:9. Penitent confession and acknowledgment of sin are the believer’s business, and the means of his deliverance from his guilt. And, 2. His encouragement thereto, and assurance of the happy issue. This is the veracity, righteousness, and clemency of God, to whom he makes such confession: He is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness, 1 John 1:9. God is faithful to his covenant and word, wherein he has promised forgiveness to penitent believing confessors. He is just to himself and his glory who has provided such a sacrifice, by which his righteousness is declared in the justification of sinners. He is just to his Son who has not only sent him for such service, but promised to him that those who come through him shall be forgiven on his account. By his knowledge (by the believing apprehension of him) shall my righteous servant justify many, Isa. 53:11. He is clement and gracious also, and so will forgive, to the contrite confessor, all his sins, cleanse him from the guilt of all unrighteousness, and in due time deliver him from the power and practice of it.