I John 2:5

Not merely repeating the proposition, Jo1 2:3, or asserting the merely opposite alternative to Jo1 2:4, but expanding the "know Him" of Jo1 2:3, into "in Him, verily (not as a matter of vain boasting) is the love of (that is towards) God perfected," and "we are in Him." Love here answers to knowledge in Jo1 2:3. In proportion as we love God, in that same proportion we know Him, and vice versa, until our love and knowledge shall attain their full maturity of perfection. his word--His word is one (see on Jo1 1:5), and comprises His "commandments," which are many (Jo1 2:3). hereby--in our progressing towards this ideal of perfected love and obedience. There is a gradation: Jo1 2:3, "know Him"; Jo1 2:5, "we are in Him"; Jo1 2:6, "abideth in Him"; respectively, knowledge, fellowship, abiding constancy. [BENGEL].

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).