This is the message which we have heard from Him and declare to you, that God is light and in Him is no darkness at all. If we say that we have fellowship with Him, and walk in darkness, we lie and do not practice the truth. But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin. (1 John 1:5-7)
Light represents what is good, pure, true, holy, and reliable. Darkness represents what is sinful and evil. The statement “God is light” means that God is perfectly holy and true and that He alone can guide us out of the darkness of sin. Light is also related to truth in that light exposes whatever exists, whether it is good or bad. God is light by nature, in His essential being, just as He is Spirit (John 4:24) and love (1 John 4:8, 16). Light refers to God’s moral character. God is holy, untouched by any evil or sin – there is no darkness at all. Because God is light, those who desire fellowship with Him must also be pure.
In the dark, good and evil look alike; in the light, they can be clearly distinguished. Just as darkness cannot exist in the presence of light, sin cannot exist in the presence of a Holy God. If we want to have a relationship with God, we must put aside our sinful ways of living. To claim that we belong to Him but then to go out and live for ourselves is hypocrisy. Christ will expose and judge such deceit.
In 1 John 1:6, John was confronting the first of three claims of the false teachers: that we can have fellowship with God and still walk in darkness. False teachers who thought that the physical body was evil or worthless taught one of two approaches to behavior: either they insisted on denying bodily desires through rigid discipline, or they approved of gratifying every physical lust because the body was going to be destroyed anyway. Obviously the second approach was more popular! Here John is saying that no one can claim to be a Christian and still live in evil and immorality. We can’t love God and court sin at the same time. To walk in darkness means to live contrary to the moral character of God, to live a sinful life. To claim fellowship with God without living a moral life or practicing the truth is to live a lie, since God cannot compromise His holiness to accommodate sin.
To walk in the light is to live in such a way that one is enlightened by the truth of who God is. When a Christian’s conduct reflects God’s moral character, then real fellowship is possible with other Christians. Our fellowship with God is dependent on walking in God’s light, where sin is revealed. Such revelation enables us to see our sins and brings us to Jesus to seek salvation. Only the blood of Jesus Christ can cleanse us from all sin, making it possible for imperfect believers to have fellowship with a Holy God.
How does Jesus’ blood purify us from every sin? In Old Testament times, believers symbolically transferred their sins to an animal, which they then sacrificed (Leviticus 4:1-35). The animal died in their place to pay for their sin and to allow them to continue living in God’s favor. God graciously forgave them because of their faith in Him, and because they obeyed His commandments concerning the sacrifice. Those sacrifices anticipated the day when Christ would completely remove sin. Real cleansing from sin came with Jesus, the “Lamb of God, who takes away the sin of the world” (John 1:29).
Sin, by its very nature, brings death – that is a fact as certain as the law of gravity. Jesus did not die for His own sins; He had none. Instead, by a transaction that we may never fully understand, He died for the sins of the world. When we commit our lives to Christ and thus identify ourselves with Him, His death becomes ours. He has paid the penalty for our sins, and His blood has purified us. Just as Christ rose from the grave, we rise to a new life of fellowship with Him (Romans 6:4).
References: NKJV Holy Bible, Life Application Bible (NIV), the Nelson Study Bible.