3 And by this we know that we have come to know him, if we keep his commandments. 4 Whoever says "I know him" but does not keep his commandments is a liar, and the truth is not in him, 5 but whoever keeps his word, in him truly the love of God is perfected. By this we may know that we are in him: 6 whoever says he abides in him ought to walk in the same way in which he walked.
7 Beloved, I am writing you no new commandment, but an old commandment that you had from the beginning. The old commandment is the word that you have heard. 8 At the same time, it is a new commandment that I am writing to you, which is true in him and in you, because[1] the darkness is passing away and the true light is already shining. 9 Whoever says he is in the light and hates his brother is still in darkness. 10 Whoever loves his brother abides in the light, and in him[2] there is no cause for stumbling. 11 But whoever hates his brother is in the darkness and walks in the darkness, and does not know where he is going, because the darkness has blinded his eyes.
Matthew Henry's Commentary on 1 John 2:3-11
Commentary on 1 John 2:3-11
(Read 1 John 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.