The seventh verse may be supposed either to look backward to what immediately preceded (and then it is walking as Christ walked that is here represented as no new, but an old commandment; it is that which the apostles would certainly inculcate wherever they brought Christ’s gospel), or to look forward to what the apostle is now going to recommend, and that is the law of fraternal love; this is the message heard from the beginning (1 John 3:11), and the old commandment, 2 John 1:5. Now, while the apostle addresses himself to the recommendation of such a practice, he is ready to give an instance thereof in his affectionate appellation: “Brethren, you who are dear to me in the bond of that love to which I would solicit you;” and so the precept of fraternal love is recommended,
I. As an old one: I write no new commandment unto you, but an old commandment, which you had from the beginning, 1 John 2:7. The precept of love must be as old as human nature; but it might admit divers enactions, enforcements, and motives. In the state of innocence, had human nature then been propagated, men must have loved one another as being of one blood, made to dwell on the earth, as being God’s offspring, and bearing his image. In the state of sin and promised recovery, they must love one another as related to God their Maker, as related to each other by blood, and as partners in the same hope. When the Hebrews were peculiarly incorporated, they must accordingly love each other, as being the privileged people, whose were the covenants and the adoption, and of whose race the Messiah and head of the church must spring; and the law of love must be conveyed with new obligations to the new Israel of God, to the gospel church, and so it is the old commandment, or the word which the children of the gospel Israel have heard from the beginning, 1 John 2:7.
II. As a new one: “Again, to constrain you to this duty the more, a new commandment I write unto you, the law of the new society, the Christian corporation, which thing is true in him, the matter of which was first true in and concerning the head of it; the truth of it was first and was abundantly in him; he loved the church, and gave himself for it: and it is true in you; this law is in some measure written upon your hearts; you are taught of God to love one another, and that because” (or since, or forasmuch as) “the darkness is past, the darkness of your prejudiced unconverted (whether Jewish or Gentile) minds, your deplorable ignorance of God and of Christ is now past, and the true light now shineth (1 John 2:8); the light of evangelical revelation hath shone with life and efficacy into your hearts; hence you have seen the excellency of Christian love, and the fundamental obligation thereto.” Hence we see that the fundamentals (and particularly the fundamental precepts) of the Christian religion may be represented either as new or old; the reformed doctrine, or doctrine of religion in the reformed churches, is new and old—new, as taught after long darkness, by the lights of the reformation, new as purged from the adulterations of Rome; but old as having been taught and heard from the beginning. We should see that that grace or virtue which was true in Christ be true also in us; we should be conformable to our head. The more our darkness is past, and gospel light shines unto us, the deeper should our subjection be to the commandments of our Lord, whether considered as old or new. Light should produce a suitable heat. Accordingly, here is another trial of our Christian light; before, it was to be approved by obedience to God; here by Christian love. 1. He who wants such love in vain pretends his light: He that saith he is in the light, and hateth his brother, is in darkness even unto now, 1 John 2:9. It is proper for sincere Christians to acknowledge what God has done for their souls; but in the visible church there are often those who assume to themselves more than is true, there are those who say they are in the light, the divine revelation has made its impression upon their minds and spirits, and yet they walk in hatred and enmity towards their Christian brethren; these cannot be swayed by the sense of the love of Christ to their brethren, and therefore remain in their dark state, notwithstanding their pretended conversion to the Christian religion. 2. He who is governed by such love approves his light to be good and genuine: He that loveth his brother (as his brother in Christ) abideth in the light, 1 John 2:10. He sees the foundation and reason of Christian love; he discerns the weight and value of the Christian redemption; he sees how meet it is that we should love those whom Christ hath loved; and then the consequence will be that there is no occasion of stumbling in him (1 John 2:10); he will be no scandal, no stumbling-block, to his brother; he will conscientiously beware that he neither induce his brother to sin nor turn him out of the way of religion, Christian love teaches us highly to value our brother’s soul, and to dread every thing that will be injurious to his innocence and peace. 3. Hatred is a sign of spiritual darkness: But he that hateth his brother is in darkness, 1 John 2:11. Spiritual light is instilled by the Spirit of grace, and one of the first-fruits of that Spirit is love; he then who is possessed with malignity towards a Christian brother must needs be destitute of spiritual light; consequently he walks in darkness (1 John 2:11); his life is agreeable to a dark mind and conscience, and he knows not whither he goes; he sees not whither this dark spirit carries him, and particularly that it will carry him to the world of utter darkness, because darkness hath blinded his eyes, 1 John 2:11. The darkness of regeneracy, evidenced by a malignant spirit, is contrary to the light of life; where that darkness dwells, the mind, the judgment, and the conscience will be darkened, and so will mistake the way to heavenly endless life. Here we may observe how effectually our apostle is now cured of his once hot and flaming spirit. Time was when he was for calling for fire from heaven upon poor ignorant Samaritans who received them not, Luke 9:54. But his Lord had shown him that he knew not his own spirit, nor whither it led him. Having now imbibed more of the Spirit of Christ, he breathes out good-will to man, and love to all the brethren. It is the Lord Jesus that is the great Master of love: it is his school (his own church) that is the school of love. His disciples are the disciples of love, and his family must be the family of love.