2:3-11 What knowledge of Christ can that be, which sees not that he is most worthy of our entire obedience? And a disobedient life shows there is neither religion nor honesty in the professor. The love of God is perfected in him that keeps his commandments. God's grace in him attains its true mark, and produces its sovereign effect as far as may be in this world, and this is man's regeneration; though never absolutely perfect here. Yet this observing Christ's commands, has holiness and excellency which, if universal, would make the earth resemble heaven itself. The command to love one another had been in force from the beginning of the world; but it might be called a new command as given to Christians. It was new in them, as their situation was new in respect of its motives, rules, and obligations. And those who walk in hatred and enmity to believers, remain in a dark state. Christian love teaches us to value our brother's soul, and to dread every thing hurtful to his purity and peace. Where spiritual darkness dwells, in mind, the judgment, and the conscience will be darkened, and will mistake the way to heavenly life. These things demand serious self-examination; and earnest prayer, that God would show us what we are, and whither we are going.
5. Not merely repeating the proposition, 1Jo 2:3, or asserting the merely opposite alternative to 1Jo 2:4, but expanding the "know Him" of 1Jo 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 1Jo 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 1Jo 1:5), and comprises His "commandments," which are many (1Jo 2:3).
hereby—in our progressing towards this ideal of perfected love and obedience. There is a gradation: 1Jo 2:3, "know Him"; 1Jo 2:5, "we are in Him"; 1Jo 2:6, "abideth in Him"; respectively, knowledge, fellowship, abiding constancy. [Bengel].