John begins this verse with the words: “But if we…”. This points to a contrast with the previous verse. Now it is about God’s children. Only of them can it be said that they walk in the light. These words also mark a condition. If we walk in the light, as He is in the light, then it has wonderful results: We have fellowship with one another, and we may know the cleansing power of the blood of the Lord Jesus’ sacrifice. John leaves open whether this condition is fulfilled. But we may state this: For God’s children, it is fundamentally true. They walk in the light. Let us look more closely at what that means.

Walking in the Light

Interestingly, it says right afterward, “as He [that is, God] is in the light.” In verse 5, John wrote that God is light. Now it is about God being in the light. That is where we now also walk. There is clearly a connection that we must understand. When it says that God is light, that relates to His unchanging nature. But now it is about God being in the light. That was by no means always so.

The term light has not only a moral meaning. It also has to do with knowledge or revelation. What is in the light is known. That contrasts with what lies in darkness (see John 3:19–21). If God today, in the time of the New Testament, “is in the light,” then before that He was “in the dark.” So it says in Exodus 20: “So the people stood at a distance, while Moses approached the thick darkness where God was” (v. 21). These verses do not merely describe the scene. They show that God was not yet fully revealed. But with the Lord Jesus everything changed. He was “God revealed in the flesh” (1 Timothy 3:16; John 1:14). Through His life and death, we have now received God’s perfect revelation. He is “the only Son, who is in the arms of the Father, He has explained Him” (John 1:18).

Living in the Full Revelation

When John writes that God’s children walk in the light, as God is in the light, it means this: We live in the light of God’s full revelation. That is equally the case for every child of God. It is not yet about whether we live accordingly in practice. It is also not an exhortation directed to us. It is the presentation of a fact. It is true that we do not always match this light. But that does not change that we fundamentally walk in the light.

Are we aware what an immense privilege it is that we may know God like this? No believer who ever lived before the Son of God became man knew God like this. This is true of God’s children who live after the finished work at the cross. No one could ever possess and enjoy such blessings as we do today.

Fellowship with One Another

If we walk in the light, as God is in the light, then something results. We, as God’s children, may enjoy fellowship in God’s family. Knowing and enjoying God is a personal blessing. But it also connects us with those who have the same share. We may reflect on what we possess together. We may reflect on what we may rejoice in together.

It may be that, regarding fellowship at the Lord’s Table, we cannot have fellowship with everyone. That is sadly a painful fact. But John is not speaking here about the house of God. He is not speaking about the body of Christ. He is speaking about the family of God. With all that divides today in Christendom, we still want to remember this. There is fellowship in the family of God.

The Blood of Jesus Christ

To the thought of fellowship, John adds another one. He connects it with a simple “and”: “and the blood of Jesus Christ, His Son, cleanses us from all sin.” When it comes to the question of sin, God exposes it relentlessly. He cannot pass over it. He must remain true to His nature. If we walk in the light, the light also shows us what we are by nature. We are sinners. But in the light, we may also recognize the value of the only means that can take away our sins: “the blood of Jesus Christ, His Son.” This blood points us to the atoning death of the Lord Jesus.

It is constantly before God. He sees it. He knows its value. That gives us security and deep peace. On the basis of the once-for-all sacrifice of the Lord Jesus, God has removed all our sins. We now stand before God without sin. It is “the blood of Jesus Christ” that cleanses us. This presents the Lord Jesus to us as a true Man. Only as Man could He give His blood as an atonement for our sins. He offered Himself without blemish through the eternal Spirit to God (Hebrews 9:14). And yet John adds: “His Son.” The One who sacrificed Himself here is far more than just a man. He is also the eternal Son of God. He stands in an eternal relationship to God the Father. Some may deny His true humanity. Others may deny His perfect deity. It remains that He is both.

Cleansing Once for All

When it says that the blood of Jesus cleanses, we have another example. It is John’s abstract style of expression, which he often uses in his letter. He is not concerned with when this cleansing happens. He is concerned with presenting the means. Only through it can cleansing from sins be accomplished. It is characteristic of the blood that it cleanses. It does so without exception from every sin. The application of the blood happens once. It does not need to be repeated. Without question, Scripture also speaks of repeated, ongoing cleansing from sins. But that cleansing happens through water, as a symbol of the word of God (see John 13).

Since we sadly can still sin, it remains necessary as long as we live on this earth. John only takes up that we also sin as God’s children from chapter 2, verse 1. But here it is about atoning cleansing through the blood of the Lord Jesus. That happens only once. For every child of God, this means deep happiness and joy. We may know this. Washed clean through the blood of the Lord Jesus, we now stand without sin before God. He Himself has taken them away. What was needed for that does not depend on us. It depends only on the atoning sacrifice of the Lord Jesus.