The Litmus Test of Light Text: 1 John 2:7-11
Introduction: The Inescapable Antithesis
The Apostle John is a master of the stark contrast. He does not deal in shades of gray. For him, the world is not a complicated spectrum of nuanced opinions; it is a battleground between two kingdoms, two realities, two ways of being. There is light, and there is darkness. There is truth, and there is the lie. There is love, and there is hate. There is life, and there is death. You are either in Christ, or you are in Adam. You are either walking in the light, or you are stumbling around in the dark. There is no middle ground, no neutral territory, no demilitarized zone.
Our modern sensibilities recoil from this. We love nuance because nuance provides a place to hide. We prefer the twilight, where we can tell ourselves we are children of the day while still clinging to the comforts of the night. We want to claim fellowship with the God who is light, while keeping a few pet hatreds tucked away in the basement of our hearts. We want to assure ourselves of our salvation, while refusing to love the very brother God has placed in our path as the primary object of our sanctification.
John will have none of it. In this passage, he takes the glorious, abstract truth that "God is light" and brings it crashing down into the most practical, tangible, and unavoidable area of our lives: our relationships with other Christians. He gives us a spiritual litmus test. You say you are in the light? Fine. Let's see how you treat your brother. Your doctrine can be impeccable, your church attendance perfect, your quiet times regular. But if you hate your brother, John says you are a liar, you are in the dark, you are blind, and you have no idea where you are going. The claim to be "in the light" is not verified by a mystical feeling or an intellectual assent. It is verified by love.
This passage forces us to confront the radical implications of the gospel. The new commandment to love one another is not a sentimental suggestion; it is the ethical bedrock of the new creation. It is the visible evidence that the darkness of the old aeon is passing away and the true light of Christ's kingdom is already dawning, both in Him and in us. The love we have for one another is not just a nice feeling; it is a participation in the very life of God. And the hatred of a brother is not just a personal failing; it is a complete contradiction of the Christian profession. It is to be a walking, talking, self-deceived oxymoron.
The Text
Beloved, I am not writing a new commandment to you, but an old commandment which you have had from the beginning; the old commandment is the word which you have heard. On the other hand, I am writing a new commandment to you, which is true in Him and in you, because the darkness is passing away and the true Light is already shining. The one who says he is in the Light and yet hates his brother is in the darkness until now. The one who loves his brother abides in the Light and there is no cause for stumbling in him. But the one who hates his brother is in the darkness and walks in the darkness, and does not know where he is going because the darkness blinded his eyes.
(1 John 2:7-11 LSB)
Old and New Commandment (v. 7-8)
John begins with what appears to be a slight contradiction, but is in fact a profound theological insight.
"Beloved, I am not writing a new commandment to you, but an old commandment which you have had from the beginning; the old commandment is the word which you have heard. On the other hand, I am writing a new commandment to you, which is true in Him and in you, because the darkness is passing away and the true Light is already shining." (1 John 2:7-8 LSB)
First, John says the commandment to love is old. How is it old? It is old in a number of ways. It was commanded in the Mosaic law: "you shall love your neighbor as yourself" (Lev. 19:18). It was the summation of the law and the prophets, as Jesus Himself taught. It was old in the sense that these believers had heard it from the very beginning of their Christian instruction. The call to love was not some advanced, graduate-level course in Christianity; it was part of the ABCs of the faith.
But then, in the very next breath, he says it is a new commandment. How can it be both old and new? This is not a contradiction; it is a progression. It is new because Jesus Christ has filled this old commandment with an entirely new depth and reality. He said, "A new commandment I give to you, that you love one another: just as I have loved you, you also are to love one another" (John 13:34). The "newness" is the standard: "just as I have loved you." The standard is no longer simply "as you love yourself," but rather the sacrificial, self-giving, substitutionary love of Christ on the cross. This is a love that lays its life down for the brethren. That is radically new.
Furthermore, it is new because of the new power available to keep it. Under the old covenant, the law was written on tablets of stone. Under the new covenant, it is written on our hearts by the Holy Spirit. This love is not just commanded; it is imparted. It is "true in Him and in you." The love of God has been poured out in our hearts (Rom. 5:5). It is Christ's love, flowing through His people.
John gives the reason for this new reality: "because the darkness is passing away and the true Light is already shining." This is inaugurated eschatology. With the coming of Christ, His death and resurrection, the light of the new creation has broken into the darkness of this fallen world. The kingdom has dawned. The age to come has overlapped with this present evil age. The darkness is a defeated, retreating foe. It is "passing away." The true Light, Jesus Christ, is not just prophesied or promised; He is "already shining." And we, as believers, are part of that dawning light. Our love for one another is the evidence that this new world has begun in us.
The Test of Fellowship: Love or Hate (v. 9)
John now applies this principle with surgical precision. He sets up the first of his three great tests of genuine faith: the moral test of obedience, the social test of love, and the doctrinal test of belief. Here is the social test.
"The one who says he is in the Light and yet hates his brother is in the darkness until now." (1 John 2:9 LSB)
Notice the formula: "The one who says..." John is deeply concerned with a profession that does not match the practice. This person makes the claim of being "in the Light." This means he claims to have fellowship with God, to be a Christian, to be saved. But this claim is flatly contradicted by his attitude toward his brother. He "hates his brother."
We need to be clear about what "hate" means here. This is not primarily about a feeling of intense emotional animosity, though it can certainly include that. In the Hebraic worldview of John, love and hate are covenantal terms. To love is to choose, to bless, to identify with, to move toward for their good. To hate is to reject, to curse, to disassociate from, to be indifferent to their well-being. It can manifest as bitterness, slander, envy, refusal to forgive, or a cold, settled indifference. It is treating a brother in Christ as though he were a stranger or an enemy.
The verdict is absolute. If you say you are in the light but you hate your brother, you are not just having a bad day. You are not just a Christian with an attitude problem. John says you are "in the darkness until now." Your profession is a lie. You are still in your unregenerate state. The light you think you have is a delusion. You have never actually left the kingdom of darkness. This is a terrifying warning against self-deception. Your relationship with God cannot be separated from your relationship with His people. To claim to love the Father whom you have not seen while hating the brother whom you have seen is, in John's economy, theological nonsense.
The Fruit of Love: Abiding and Stability (v. 10)
In contrast to the one who hates, John describes the one who truly loves.
"The one who loves his brother abides in the Light and there is no cause for stumbling in him." (1 John 2:10 LSB)
Here is the positive proof of life. The one who genuinely "loves his brother" demonstrates that he "abides in the Light." To abide is to remain, to dwell, to make your home in. This is not a fleeting visit to the light, but a settled residence. Love for the brethren is the natural, constant fruit of a life that is rooted in God, who is Light and Love.
And this love has a profound effect: "there is no cause for stumbling in him." This can be understood in two ways, and both are likely intended. First, the one who loves is not easily tripped up. His path is illuminated. Love provides moral clarity and stability. When you are walking in love, you are not easily offended, you are not constantly suspicious, you are not looking for faults. You are walking on a well-lit path and can see the obstacles clearly. Second, the one who loves does not become a stumbling block to others. A hateful, bitter Christian is a terrible witness. He causes others to stumble, both believers and unbelievers. But a life characterized by genuine, Christ-like love is a stable, solid testimony that builds others up and points them to the sure foundation.
The Consequence of Hate: Blindness and Disorientation (v. 11)
John concludes by returning to the stark reality of the one who hates, spelling out the consequences in no uncertain terms.
"But the one who hates his brother is in the darkness and walks in the darkness, and does not know where he is going because the darkness blinded his eyes." (1 John 2:11 LSB)
This is a picture of compounding spiritual disaster. First, his position is "in the darkness." He is in enemy territory, the domain of Satan. Second, his practice is he "walks in the darkness." His whole life is characterized by this. It is not a momentary lapse, but his constant environment and direction. Third, his perception is gone: he "does not know where he is going." He is utterly disoriented. He thinks he is on the road to heaven, but he is actually wandering in circles, or worse, heading straight for a cliff. He has no spiritual bearings.
And the reason for this tragic condition is given: "because the darkness blinded his eyes." This is a spiritual and judicial blindness. The hatred he harbors is not just a symptom of his darkness; it is the very thing that perpetuates it. Sin has a blinding effect. When you refuse to forgive, when you nurse a grudge, when you harbor bitterness, you are pulling the shades down on your own soul. You become incapable of seeing reality as it is. You cannot see God clearly, you cannot see your brother clearly, and you cannot see yourself clearly. You are trapped in a prison of your own making, and you have lost the ability to even see the bars.
Love as the Logic of Light
So what is the takeaway for us? It is this: Christian fellowship is not optional. Love for the brethren is not an elective. It is the central, non-negotiable evidence of our new birth. We live in a culture that prizes expressive individualism above all else. We are taught to think of our faith as a private, personal journey between "me and Jesus." John demolishes that idea.
Your vertical relationship with God is proven by your horizontal relationships with His people. You cannot say you are right with God if you are wrong with your brother. This means we must be ruthless in rooting out all forms of hatred from our hearts. Bitterness, resentment, slander, gossip, envy, and unforgiveness are not minor sins for a Christian; they are a declaration that we are walking in darkness. They are a denial of the gospel.
When God brought you from darkness to light, He did not just save you as an isolated individual. He adopted you into a family. And He expects you to love your siblings. This love is not a syrupy sentimentality. It is a rugged, covenantal commitment. It is bearing with one another, forgiving one another, speaking truth to one another, serving one another, and preferring one another.
This is how the world knows we are His disciples: not by our doctrinal precision alone, not by our political victories, but by our love for one another (John 13:35). Our love is the apologetic. When a watching world, drowning in the darkness of its own hatreds and divisions, sees a community of people from different backgrounds who genuinely love each other with the self-sacrificing love of Christ, they see the light. They see that the darkness is passing away, and the true Light is indeed shining.