21 My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous. 2 He is the propitiation for our sins, and not for ours only but also for the sins of the whole world.
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.
Matthew Henry's Commentary on 1 John 2:1-7
Commentary on 1 John 2:1-2
(Read 1 John 2:1-2)
When have an Advocate with the Father; one who has undertaken, and is fully able, to plead in behalf of every one who applies for pardon and salvation in his name, depending on his pleading for them. He is "Jesus," the Saviour, and "Christ," the Messiah, the Anointed. He alone is "the Righteous One," who received his nature pure from sin, and as our Surety perfectly obeyed the law of God, and so fulfilled all righteousness. All men, in every land, and through successive generations, are invited to come to God through this all-sufficient atonement, and by this new and living way. The gospel, when rightly understood and received, sets the heart against all sin, and stops the allowed practice of it; at the same time it gives blessed relief to the wounded consciences of those who have sinned.
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.