[2:1] 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.  He is the propitiation for our sins, and not for ours only but also for the sins of the whole world.  And by this we know that we have come to know him, if we keep his commandments.  Whoever says “I know him” but does not keep his commandments is a liar, and the truth is not in him,  but whoever keeps his word, in him truly the love of God is perfected. By this we may know that we are in him:  whoever says he abides in him ought to walk in the same way in which he walked. (1 John 2:1-6 ESV)
So far John has told us that the life of God was manifested in the incarnation of the Son - the one whom the apostles saw and heard and touched. It is this life-giving Son of God with whom John invites his readers to have fellowship (and thereby have fellowship also with the Father and the apostles themselves), and the message that this same Son of God and font of life proclaims through his apostles is the message that God is light. Fellowship with God through the life giving Son brings a life lived in the light, no longer hiding in the shadows, no longer needing to pretend at sinless perfection. Life in the light through fellowship with the Son (which is nothing less than participation in the very life of the Triune God) frees us up to confess our own sins with the assurance that the the Son will cleanse us with the fiery light of his presence.
But John has more to say. He is no encourager of sin. While it is true that to deny our sins is to deceive ourselves and to make God a liar, nevertheless, John has written in order that those who here his message may not sin. St. John’s writings thrive on these tensions.
Here at the beginning of chapter 2 the apostle tells us that his goal in speaking about the light and life and fellowship and forgiveness that has appeared in the manifestation, the incarnation, of the Son of God has been to keep us from sin. But ever mindful of his goal of encouragement he tells us almost in the same breath that if we do sin not only are we forgiven, but we are forgiven because Jesus Christ the righteous, the bringer of life, is our advocate. He stands in heaven not to plead with a harsh and uncompromising Father, but as the bridge between fallen humanity and divinity, the divine-human Son of God who in his death for sins by which he became a propitiation (that is one who bears wrath in our stead) has brought our human lives into the fellowship of the Godhead. And as if that weren’t enough, John then tells us that Jesus propitiatory death was no mere parochialism, it wasn’t the death of one man for a few friends, or a tribal God for a tribal people, but it was the world shaking death of the Son of God which is able to accomplish redemption for the whole world.
And how will we know that we stand covered under such a propitiation? (For we know that while Christ died as a propitiation for the sins of the whole world, there are those in the world who will reject such benevolence and refuse the fellowship offered.) We will know it by our actions. Now at this point we may start to get a little queasy; at times calvinistic Christians can seem almost allergic to talk about good works, righteous actions, or commandment keeping. Unfortunately this makes us allergic to parts of the Bible. While it is absolutely true that we can never put God in our debt by anything we do or don’t do, it is equally true that God cares deeply about our behavior and our behavior manifests the kind of relationship we have with God.
And so John says that we can know that we know this life giving Son, this God of light, this one who has become a propitiation for our sins by noting that we keep his commandments. This means no worm theology. This means it will not do to adopt the modern reformed asceticism that wallows in the mire of total depravity and radical grace, never recognizing that the life of one who has been put into the light is a life transformed and characterized by obedience, which is the harbinger of confidence that we do in fact know God. Knowing God manifests itself in a growing family resemblance. God made us in his image, and as we come to know him and to have fellowship with him that image, which has been marred by sin, begins to shine through brighter and brighter.
But John’s language gets even starker. He says that just as one who denies sin and the need for forgiveness, the need for a propitiation, deceives himself and calls God a liar, so the one who claims to know God but does not keep his commandments is himself a liar. For to know God is to be in the light because God himself is light, and no one who is in the light can continue to walk in darkness. Again, as we’ve said before this is not a call to doubt our standing with God any time we disobey. John has covered that. We have an advocate. Rather, John’s point is that my confidence in that propitiation, and my confidence that it covers my sins is to be found in my obedience to his command, which is the evidence that I am in the light.
Again, the images swirl back on themselves. If I have life it is because I have heard the proclamation that God is light and been brought into the light and if I am in the light I will not walk as one in the darkness but according to light, just as He who is light walked among us (v.6), and thus I will keep his commandments. It’s a package deal: life, light, forgiveness and obedience. You can’t have any without having all.