In Ephesians 4:17—5:21, the apostle Paul gives practical yet challenging instruction in holy living. The path to holiness includes imitating God (like children imitating a parent) by walking in love (verses 5:1–2) and walking as “children of light” (verses 5:8–9). The opposite of holy living is characterized in the Bible as “walking in darkness” (Isaiah 9:2; see also Proverbs 2:13), which is why Paul warns, “Take no part in the unfruitful works of darkness, but instead expose them” (Ephesians 5:11, ESV).
Throughout Scripture, darkness symbolizes sin and its effects (Proverbs 2:12–15; Matthew 6:23; Isaiah 5:20; Isaiah 29:15). The word unfruitful in Ephesians 5:11 means “having no beneficial use, unproductive.” The works of darkness are unfruitful because they end in death, but the fruit of righteousness “leads to holiness, and the result is eternal life” (Romans 6:20–22).
By telling the Ephesians what behaviors to avoid, Paul outlines the unfruitful works of darkness: “But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God’s holy people. Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving. For of this you can be sure: No immoral, impure or greedy person—such a person is an idolater—has any inheritance in the kingdom of Christ and of God” (Ephesians 5:3–5).
Paul advised the Romans to “cast off the works of darkness and put on the armor of light.” Then he listed other dark deeds such as “orgies and drunkenness, . . . sexual immorality and sensuality, . . . quarreling and jealousy” (Romans 13:12–13, ESV).
To the Corinthians, Paul explained that light and darkness could not mix: “How can light live with darkness? What harmony can there be between Christ and the devil? How can a believer be a partner with an unbeliever? And what union can there be between God’s temple and idols? For we are the temple of the living God. . . . Let us cleanse ourselves from everything that can defile our body or spirit. And let us work toward complete holiness because we fear God” (2 Corinthians 6:14—7:1, NLT).
Paul described people before salvation as being “dead because of your disobedience and your many sins. You used to live in sin, just like the rest of the world, obeying the devil—the commander of the powers in the unseen world. He is the spirit at work in the hearts of those who refuse to obey God” (Ephesians 2:1–2, NLT). In this dead state, “their minds are full of darkness; they wander far from the life God gives because they have closed their minds and hardened their hearts against him” (Ephesians 4:17–18, NLT). Jesus said, “Whoever walks in the dark does not know where they are going” (John 12:35). Unbelievers wander about in the darkness until their eyes are opened “so they may turn from darkness to light and from the power of Satan to God. Then they will receive forgiveness for their sins and be given a place among God’s people” (Acts 26:18, NLT).
God’s people are made alive as children of light (1 Thessalonians 5:4–5). They avoid unfruitful works of darkness because they have been rescued “from the dominion of darkness and brought” into the kingdom of Christ’s light (Colossians 1:13).
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). The unsaved person walks in darkness, performing unfruitful works of darkness, while the child of God puts on the armor of light and works toward complete holiness as Jesus directed: “You are the light of the world—like a city on a hilltop that cannot be hidden. No one lights a lamp and then puts it under a basket. Instead, a lamp is placed on a stand, where it gives light to everyone in the house. In the same way, let your good deeds shine out for all to see, so that everyone will praise your heavenly Father” (Matthew 5:14–16, NLT).
Paul told the Ephesians to expose the unfruitful works of darkness. He may have been speaking about the sins of fellow members of Christ’s body. Jesus taught believers to hold one another accountable for how they live and to work to restore those who get entangled in sin (Matthew 18:15–20; Luke 17:3; see also Galatians 6:1; Psalm 141:5; Hebrews 12:13; James 5:19–20; 1 Thessalonians 5:14).
But Paul may also have been referring to exposing the sins of disobedient non-believers. Jesus stated, “All who do evil hate the light and refuse to go near it for fear their sins will be exposed. But those who do what is right come to the light so others can see that they are doing what God wants” (John 3:20–21, NLT). We expose unfruitful works of darkness by shining the light of God’s truth into a dark world. The apostle John explained, “This is the message we have heard from him and declare to you: God is light; in him there is no darkness at all. If we claim to have fellowship with him and yet walk in the darkness, we lie and do not live out 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, his Son, purifies us from all sin” (1 John 1:5–7).
Darkness cannot remain in the light of God’s truth. Whether we expose unfruitful works of darkness in the church or shine light into a lost and dying world, we are fulfilling our mission on earth—transforming darkness into light as those living in darkness become people of the light (Isaiah 42:6–7; John 12:46; 2 Corinthians 4:6; 1 Peter 2:9; 2 Peter 1:19).