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; and he is the atoning sacrifice for our sins, and not for ours only but also for the sins of the whole world. Now by this we may be sure that we know him, if we obey his commandments. Whoever says, “I have come to know him,” but does not obey his commandments, is a liar, and in such a person the truth does not exist; but whoever obeys his word, truly in this person the love of God has reached perfection. By this we may be sure that we are in him: whoever says, “I abide in him,” ought to walk just as he walked. (1 John 2:1-6, NRSV)

John, in his first epistle, writes as a concerned and caring father who wants the best for his children. He knows the best thing for those in his care is to have fellowship with God. He expresses this in the opening chapter of his letter: “What we have seen and heard we also declare to you that you may have fellowship with us; and indeed our fellowship is with the Father and with His Son Jesus Christ” (1 John 1:3).

John carries this concern into chapter two. John writes so that his hearers (this includes us) won’t fall into sin, because sin separates us from God and breaks our fellowship with him. But John doesn’t speak threatening words of punishment like an angry father. Instead, he points us to the only power that can solve their sin problem: Jesus.

John says Jesus is our advocate because “he is the atoning sacrifice for our sins and not only ours but also for the sins of the whole world.” An advocate is one who speaks on behalf of another because the advocate knows the one for whom they advocate. “It denotes a friend called upon to give help, either by pleading or giving evidence, or in virtue of [their] position and power” (Brooke, Epistles, 24).

John continues, “Now by this we may be sure we know him if we obey his commandments.” Or, put another way, “We may be sure that we know our advocate, and he knows us if we obey his commandments.” At first glance, this can terrify us. How can we obey all of God’s commandments? We are sinners; even still after our baptisms. The fault comes from our understanding of the word “commandments.” We understand the word in its narrowest sense. We think primarily of the ten commandments — the summary of God’s rules and laws. But, John means it in a broader sense. He means instruction and teaching. Not just “do’s and don’ts,” but words of truth about God and his Son, Jesus, our advocate.

In 1 John 3:23, John writes that God’s command, his instruction, is to “believe in the name of his Son Jesus Christ.” Those who claim to know Jesus, but don’t believe in him as their advocate fail to speak the whole truth and so lie. They only know part of Jesus and so make Jesus into what they want him to be. Jesus, who is the truth, is not in them.

John speaks to the extent to which we have Jesus, God’s Word, in us. If the truth is in us, that is, if we believe in Jesus Christ as our advocate, then God’s love, which is Jesus Christ and his righteousness, is in us perfectly, meaning: fully and completely, lacking nothing. God does not give us half of Jesus, but all of Jesus. He does not give us a down payment and then pay us in full after we meet some condition of goodness. We receive all of Christ’s righteousness and so all of his perfect fellowship with the Father.

John says that we know we have fellowship with God—he in us and we in him—if we walk in the way Jesus walked. What does it mean to walk as Jesus walked? It means simply we walk to the cross. It is on the cross, with Christ, where our sins die; where our sinful natures die; where we die.

We walk to the cross by the faith that God bestows on us, not by our own power, reason, or might. The cross appears to the world as an unreasonable solution to the problem of sin. But, this is where John’s letter drives us. It points us not to any good works we could do, but to the cross and to Jesus’ atoning sacrifice on it for us.

By his death for us, Jesus earned forgiveness and life for us, and by it, he advocates for us until the end of time. He presents his righteousness to the Father as our righteousness. And it is his righteous advocating on our behalf that opens the door for us so that we can live in fellowship with God.