Believers have learned Christ, been sealed by the Holy Spirit, and become light in the Lord. Therefore they must leave behind their former sinful way of life and live in a manner that fits the new humanity God has created in Christ. Paul applies this to everyday matters such as speech, anger, work, purity, worship, thanksgiving, and relationships, while also giving serious warnings about continuing in immoral patterns.

Paul begins with a solemn charge, not a casual suggestion. In the Lord, he insists that believers must no longer live like the surrounding pagan world. That former way of life is not merely socially different; it is spiritually ruined from the inside out. Paul traces its downward course: empty thinking, darkened understanding, separation from the life of God, ignorance rooted in hardness of heart, loss of moral sensitivity, and then open surrender to impurity and greed. The problem, then, is not simply a lack of information. It is moral and spiritual resistance to God, and that resistance shows itself in corrupt living.

That is not what these believers were taught when they came to know Christ. Paul’s wording is striking. They did not merely learn ideas about Christ; they learned Christ Himself, because the truth is in Jesus. What they were taught involved a decisive break with their former way of life. They were to put off the old man—that is, the old self or old way of life—bound up with deceitful desires and ongoing corruption. They were to be renewed in the spirit of their minds and to put on the new man, the new self or new humanity created according to God in righteousness and holiness that come from the truth. This is not bare self-improvement. It is moral transformation rooted in the new identity God has given, and it is expressed in the shared life of His people.

Paul then shows what this looks like in the life of the church. Falsehood must give way to truth, because believers are members of one another. Anger is not automatically sinful, but it must not be allowed to become sin. It must be dealt with quickly, because lingering anger gives the devil an opening. The thief must not only stop stealing, but begin honest labor, doing good work with his own hands so that he can share with those in need. Speech must not be rotten, harmful, or corrupting. Instead, it should fit the need of the moment and build others up, so that it gives grace to those who hear.

In this same context Paul warns, do not grieve the Holy Spirit of God. The Spirit is not an impersonal force. He is the personal divine presence who has sealed believers for the day of redemption. For that reason, sins such as destructive speech, bitterness, rage, slander, and malice are not merely social failures. They are offenses against the Holy Spirit, who marks God’s people as His own. In contrast, believers are to be kind, compassionate, and forgiving toward one another, because God in Christ forgave them.

This leads naturally into the next section. Believers are to imitate God as dearly loved children. Yet that imitation is not vague or abstract. It is defined by Christ’s love: He loved us and gave Himself up for us as a sacrifice, a fragrant offering to God. So walking in love means costly, self-giving love shaped by Christ’s cross, not sentimental language or mere kindness detached from holiness.

Because of that, certain sins must not characterize the church at all. Sexual immorality, every kind of impurity, and greed are unfitting for saints. Vulgar speech, foolish talk, and coarse joking are also out of place. Thanksgiving is to take their place. Paul then gives a very serious warning: the immoral, impure, and greedy person has no inheritance in the kingdom of Christ and God. Greed is not treated as a minor flaw; it is idolatry, a rival devotion that competes with God. Paul does not soften this warning. He says believers must not be deceived by empty words, because God’s wrath comes because of these things upon the sons of disobedience. Therefore they must not join such people in these practices.

Paul next explains this in terms of identity. They once were darkness, but now they are light in the Lord. He does not merely say they were in darkness; he says they were darkness, and now they are light. The contrast is deep and decisive. Therefore they must walk as children of light. The fruit of the light consists in goodness, righteousness, and truth, and believers are to keep learning what pleases the Lord. They must not share in the unfruitful works of darkness, but instead expose them. In context, this exposure is not a call to graphic discussion or unhealthy fascination with evil. Paul immediately says the secret things done in darkness are shameful even to mention. The point is that light makes evil visible. Believers expose darkness by living openly in holiness and by truthful reproof where needed.

The call in 5:14—“Awake, sleeper, and arise from the dead, and Christ will shine on you”—serves as an urgent summons to leave spiritual stupor and come into Christ’s light. The exact source of the wording is uncertain, but its purpose in the passage is clear.

Because the days are evil, believers must walk carefully, not foolishly but wisely. They are to make the most of their opportunities and understand the Lord’s will. Paul then contrasts two controlling influences: do not get drunk with wine, which leads to reckless living, but be filled by the Spirit. In this passage, being filled by the Spirit is not presented as a private mystical experience or as something reserved for a few. It is seen in the shared life of believers: speaking to one another with psalms, hymns, and spiritual songs; singing and making melody in the heart to the Lord; giving thanks always to God the Father for all things in the name of the Lord Jesus Christ; and submitting to one another out of reverence for Christ. These are visible expressions of Spirit-filled life in the church.

Taken together, this passage calls the church to live in a way that fits the new humanity God has created in Christ. Paul grounds every command in the truth of who believers now are, whom they belong to, what Christ has done, and the coming day of redemption. He also makes clear that ongoing patterns of impurity, greed, corrupt speech, and participation in darkness are not small matters. They contradict life in Christ and stand under the warning of God’s wrath.