Light is a common metaphor in the Bible. Proverbs 4:18 symbolizes righteousness as the “morning sun.” Philippians 2:15 likens God’s children who are “blameless and pure” to shining stars in the sky. Jesus used light as a picture of good works: “Let your light shine before others, that they may see your good deeds” (Matthew 5:16). Psalm 76:4 says of God, “You are radiant with light.”
If light is a metaphor for righteousness and goodness, then darkness signifies evil and sin. We are told in 1 John 1:5 that “if we claim to have fellowship with him yet walk in the darkness, we lie and do not live by the truth.” Verse 5 says, “God is light; in him there is no darkness at all.” Note that we are not told that God is a light but that He is light. Light is part of His essence, as is love (1 John 4:8). The message is that God is completely, unreservedly, absolutely holy, with no admixture of sin, no taint of iniquity, and no hint of injustice.
If we do not know light, we do not know God. Those who know God, who walk with Him, are of the light and walk in the light. They are made partakers of God’s divine nature, “having escaped the corruption in the world caused by evil desires” (2 Peter 1:4).
Jesus said, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life” (John 8:12). To “walk” means to make progress. Therefore, we can infer from this Scripture that Christians are meant to grow in holiness and to mature in faith as they follow Jesus (see 2 Peter 3:18).
It is God’s plan that believers become more like Christ every day. “You are all children of the light and children of the day. We do not belong to the night or to the darkness” (1 Thessalonians 5:5). He is the Creator of physical light, as well as the Giver of spiritual light, by which we can see the truth. Light exposes that which is hidden in darkness; it shows things as they really are. To walk in the light means to know God, understand the truth, and live in righteousness.
Christ followers must confess any darkness within themselves—their sins and transgressions—and allow God to shine His light through them.
Christians cannot sit idly by and watch others continue in darkness, knowing that those in the darkness of sin are destined for eternal separation from God. The Light of the World desires to banish the darkness and bestow His wisdom everywhere (Isaiah 9:2; Habakkuk 2:14; John 1:9). In taking the light of the gospel to the world, we must by necessity reveal things about people that they would rather leave hidden. Light is uncomfortable to those accustomed to the dark (John 3:20).
Jesus, the sinless Son of God, is the “true light” (John 1:9). As adopted sons of God, we are to reflect His light into a world darkened by sin. Our goal in witnessing to the unsaved is “to open their eyes and turn them from darkness to light, and from the power of Satan to God” (Acts 26:18).
 Got Questions Ministries. (2010). Got Questions? Bible Questions Answered. Bellingham, WA: Logos Bible Software.