I John 2:8

a new commandment--It was "old," in that Christians as such had heard it from the first; but "new" (Greek, "kaine," not "nea": new and different from the old legal precept) in that it was first clearly promulgated with Christianity; though the inner spirit of the law was love even to enemies, yet it was enveloped in some bitter precepts which caused it to be temporarily almost unrecognized, till the Gospel came. Christianity first put love to brethren on the new and highest MOTIVE, instinctive love to Him who first loved us, constraining us to love all, even enemies, thereby walking in the steps of Him who loved us when enemies. So Jesus calls it "new," Joh 13:34-35, "Love one another as I have loved you" (the new motive); Joh 15:12. which thing is true in him and in you--"In Christ all things are always true, and were so from the beginning; but in Christ and in us conjointly the commandment [the love of brethren] is then true when we acknowledge the truth which is in Him, and have the same flourishing in us" [BENGEL]. ALFORD explains, "Which thing (the fact that the commandment is a new one) is true in Him and in you because the darkness is passing away, and the true light is now shining; that is, the commandment is a new one, and this is true both in the case of Christ and in the case of you; because in you the darkness is passing away, and in Him the true light is shining; therefore, on both accounts, the command is a new one: new as regards you, because you are newly come from darkness into light; new as regards Him, because He uttered it when He came into the world to lighten every man, and began that shining which even now continues." I prefer, as BENGEL, to explain, The new commandment finds its truth in its practical realization in the walk of Christians in unio…

Here the apostle encourages against sins of infirmity (Jo1 2:1, Jo1 2:2), shows the true knowledge and love of God (Jo1 2:3-6), renews the precept of fraternal love (Jo1 2:7-11), addresses the several ages of Christians (Jo1 2:12-14), warns against worldly love (Jo1 2:15-17), against seducers (Jo1 2:18, Jo1 2:19), shows the security of true Christians (Jo1 2:20-27), and advises to abide in Christ (Jo1 2:28, Jo1 2:29).

2:8 Yet it is also new: Jesus’ command provided the new basis for their love in his own demonstration of love to the disciples (John 13:1-17). • the darkness is disappearing and the true light is already shining: The light of the Good News expels darkness. Darkness cannot overcome it, especially where believers are living out the love that is in Christ.