3 Now by this we know that we know Him, if we keep His commandments. 4 He who says, "I know Him," and does not keep His commandments, is a liar, and the truth is not in him. 5 But whoever keeps His word, truly the love of God is perfected in him. By this we know that we are in Him. 6 He who says he abides in Him ought himself also to walk just as He walked.
7 Brethren, [1] I write no new commandment to you, but an old commandment which you have had from the beginning. The old commandment is the word which you heard from the beginning. 8 Again, a new commandment I write to you, which thing is true in Him and in you, because the darkness is passing away, and the true light is already shining. 9 He who says he is in the light, and hates his brother, is in darkness until now. 10 He who loves his brother abides in the light, and there is no cause for stumbling in him. 11 But he who hates his brother is in darkness and walks in 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.