1 John 1:7 ⁷But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin.

When the positive condition of living in the light is met, the outcome is cleansing from all sin. The answer to the darkness is allowing the light of God to penetrate the darkness of our hearts. Light is connected to God in verse 5. It represents both relationship and obedience, both spiritual and practical, and both the heart and the life. The clearest and most detailed light from God comes through the revelation of Jesus Christ, who is the Light of the world (John 8:12). God has given directions for how to walk in imitation of his character. Our goal is to live in God’s image, which is the best scenario for a good life on earth and the only sure hope for eternal life in heaven.

When this condition is met, two outcomes are given in this verse. The first a more complete fellowship (koinōnian) with one another. The barriers created by sin are removed and our hearts are filled with love for one another, just as Jesus commanded (John 13:35). Many things create walls between people. Often, these walls can be summarized as guilt before God and shame before others. We do not feel worthy to be in fellowship with others because we feel dirty and sinful because of the darkness within us. When this darkness is replaced by light, we can find our self-worth in Jesus and not in people’s assessment of us.

The second outcome is cleansing of our sin. Cleanses (katharizei) means to purify or to heal. It can have a cultic nuance of declaring something ceremonial clean. It is often used in the New Testament for how the heart or conscience is purified from sin (James 4:8; Hebrews 9:14). God’s light will reveal what we need to confess. Walking is a choice we must make. It is not easy, especially when the darkness has deceived us into believing it is acceptable and has no consequences.

The more we walk in God’s light, the more our inner person, our thoughts and motives, are cleansed from the pull of sin. Our relationships with others that once were influenced by selfish motives improve because we love others in the character and reflection of God’s love for us show in Jesus.

All this is made possible because of the blood of Jesus. The atonement of sin is made possible because of Jesus’ sacrifice on the cross. His blood, representing his human life, purifies the inner person, restoring us into right relationship with God and with others.

The verb tense of cleanses word is present, indicating a continual process. Our cleanses is both instant and gradual. Jesus’ sacrifice is more than sufficient to take care of any sin problem we have. However, life is dynamic and we face continual temptation and need to continually grow in our faith and dependence on God. The blood of Christ continually sanctifies our inner person and takes care of all our struggles with sin and removes the influence of the power of sin in our lives. John will highlight that idea more in the following verses.