Ephesians 4:17-19

We come now to understand our walk in Christ as including a new mind of purity, love, wisdom, and light, all for the sake of unity to the glory of God. Paul’s practical application, which began in Ephesians 4:1 with the words, “live a life worthy of the calling you have received,” leans heavily on Biblical doctrine, and to separate application from doctrine leaves us with legalism.

¹⁷So I tell you this, and insist on it in the Lord, that you must no longer live as the Gentiles do, in the futility of their thinking. ¹⁸They are darkened in their understanding and separated from the life of God because of the ignorance that is in them due to the hardening of their hearts. ¹⁹Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, with a continual lust for more.

Paul continues his train of thought from the previous section of Ephesians 4. He has pointed to diversity among believers unto unity. He has pointed to the importance of intellectual growth unto unity in the fullness of Christ. And now he insists on right living; the basis for right living is right thinking, unlike that of the Gentiles (pagans). Paul says to the Christian, “Learn the truth from those whom God has ordained to teach it, and from the indwelling Holy Spirit; then go and serve one another in love. As that happens, the body of Christ will be unified in growth to maturity (intellectual understanding of the faith, doctrine, and experiential knowledge of Jesus Christ), attaining the fullness of Christ. And because that’s how it works, we must live according to the right thinking in which we are growing.” What does that look like? Paul will give six positive answers to that question in v25-32 and into chapter 5, but for now, he focuses on the negatives. Paul says not live like a Gentile, and he means that we are not to live a life that is not centered on God, a life that is not God-honoring and God-focused – like the Gentiles do. No matter whether they worship many gods or none, the Gentiles are worshiping only themselves. Christians, though commanded to love unbelievers, are not to live or think or believe or desire or speak or behave like them.

Paul says first, in v17, that he is telling you not to live like worldly people. Christians are in the world but not of the world. But there’s more. Paul is insisting in the Lord that you not live like worldly people. Other translations say it much better: “So this I say, and affirm together with the Lord....” The Lord Jesus is insisting that we live rightly. It’s not a recommendation; it’s a command (1 Thessalonians 2:13). One day, we’ll give an account before the Lord regarding how we handled this teaching of Paul. But Paul doesn’t just leave it there. He goes on to explain what that looks like. He starts with futile thinking.

Unbelievers live in vain and futile thinking, darkened in their understanding. They are ignorant of the truth of God. They are stupid morons, just as much as they are sinners. And if it’s right to warn them about their sinful status before God, which it is, according to Vincent Cheung, it’s also right to tell them that they are stupid morons and demand their repentance and belief on Christ for justification and sanctification. This passage is similar to Romans 1, but the emphasis here is from the human perspective; as God hardened pharaoh’s heart, so pharaoh hardened himself. Furthermore, unbelievers are excluded from “the life of God” (regeneration) because of their ignorance, which is due to their hardness of heart. They indulge in a moral resistance to the truth of the commands of God in them. And they have become callous; they are no longer sensitive to God. They cherish impurity for the sake of vanity and sensuality. And they lust for more. Paul says not to live like that. And that command hits home. The fact that Paul has to tell Christians not to live like that tells us that we, as Christians, will at times be tempted to live like that, desire that, lust for sensual impurity. And we know it. We must fight that kind of life. Why? Ligon Duncan tells us:

“Paul is emphasizing there that there is a moral component to Christianity that sets Christianity apart from everyone else in the world, that sets Christians apart, that sets the church apart from everyone else in the world. And, my friends, it is that distinction that is so crucial to our witness in the world, because when the world looks at us and says ‘You are not so different from me,’ the effectiveness of our witness is sapped because the claim of our message to produce in us the workings of God’s grace so that we are made to be what God intended us to be originally is undermined, undercut. And so it is precisely in the church’s response to this exhortation of Jesus and Paul that we have the most effective aspect of our witness-bearing to the world.”