Ephesians 5:5-7
For this you know, that no sexually immoral or unclean person, nor a greedy person—who is an idolater—has any inheritance in the kingdom of Christ and God. Let no one deceive you with useless words, for it is because of these things the wrath of God comes upon the sons of disobedience. Therefore, do not be partakers with them.
This passage tears apart so many modern misconceptions that it's hard to know where to start!
It is as though the Holy Spirit knew in advance the sort of false teachings that would be popular in modern Christianity.
There are three passages that say what Ephesians 5:5 says, that the unrighteous cannot inherit the kingdom of God. There is Ephesians 5:5 itself, 1 Corinthians 6:9-11, and Galatians 5:19-21. Every one of them adds an emphasis. 1 Cor. 6:9-11 and Eph. 5:5 warn us not to be deceived, and in Gal. 5:19-21 Paul makes a point that he's repeating himself.
Despite these warnings, the false doctrine of "eternal security" (even the term "once saved, always saved" is closer to Scriptural phrase than "eternal security") causes millions of Christians and thousands of supposed Bible experts—pastors, teachers, and even seminary professors—to argue that the unrighteous can "go to heaven." What they man by this is that immoral, unclean, and greed men can inherit the kingdom of God eternally, but they can't experience the kingdom of God while here on earth.
Beyond the fact that this is a deplorable dance around the apostle's words that ought to embarrass us, Paul seems to take care in Ephesians 5:5 to specifically refute the doctrine. He tells us that the immoral, unclean, and greedy will not have any inheritance in the kingdom of Christ and God. Maybe the apostle added that last part because there are people who will want to distinguish between the kingdom of Christ, the kingdom of God, and the kingdom of heaven in order to find some entrance into one of those for people who do not keep the commandments of Christ and thus do not know God (1 John 2:3-4).
I am not objecting to distinguishing between the kingdom of heaven and the kingdom of God. Better theologians than I have shown a difference in application, and I have not devoted time to the subject yet. I am, however, making it clear that you cannot be in one and out of another. God is one, and he doesn't keep a person out of the kingdom of God on earth, then admit you to the kingdom after you die.
Condemned for Sin or for Unbelief?
One other modern doctrine addressed here is that Jesus paid for all sin, and therefore no one is judged for sin!
Paul makes it very clear that the sons of disobedience are still judged for "these things"—sexual immorality, uncleanness, and greed—that the wrath of God comes upon the sons of disobedience. It is not merely for unbelief.
Consider, too, the context of this passage. It is not just the sons of disobedience who are judged for sexual immorality, uncleanness, and greed. Christians are as well! We will miss out on any inheritance in the kingdom of Christ and of God if we continue in these things without repentance.
Paul does not bring up the sons of disobedience because he has a doctrinal point to make about them. The context is still us, the Christians. We won't inherit God's kingdom if we live like the sons of disobedience. It's because of their sins that God's wrath comes upon them. Seeing that, Paul warns us not to be partakers with them.
The morass of misunderstanding about the atonement, faith, and works among modern Christians is great, and there are dozens of misunderstood verses—each as easily understood as Ephesian 5:5-7—that need to be "realigned" in our mind. I've taken a beginning at doing that in the salvation section of this web site and on my Christian history site's Sola Fide page.