Summary: We cannot go back to the old self, and no where is the distinction between the old self and the new self found than in the area of sexuality.
We wrapped up two Sundays ago the first section of chapter 4 on the theme of church unity. We now move into the subject of what constitutes Christian moral behavior. Look with me at the text, Ephesians 4:17-19.
Now this I say and testify in the Lord, that you must no longer walk as the Gentiles do, in the futility of their minds. 18 They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart. 19 They have become callous and have given themselves up to sensuality, greedy to practice every kind of impurity.
The first phrase – Now this I say and testify in the Lord – indicates a new subject. Paul is now moving toward another focus, which is important to him. To “testify in the Lord” is a solemn declaration.
So what is weighing on Paul’s mind? It is that walk which he first spoke of in verse 1: “you must no longer walk as the Gentiles do.” In verse 1, the walk involved the manner in which Christians are to build up one another as the body of Christ. Here the walk is presented as a contrast to the believers’ former way of life. That is what is meant by “Gentiles” in this instance. Jonny McGreevy will tell us that there are two kinds of people in the world: those who are Irish and those who wish they were. Scripture actually had a neat division as well up until Christ’s coming: those who were Jewish, belonging to the covenant people of God, and those who were not, i.e. Gentiles.
Look at Paul’s description of the Gentiles back to 2:11-12:
Therefore remember that at one time you Gentiles in the flesh, called “the uncircumcision” by what is called the circumcision, which is made in the flesh by hands— 12 remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world.
It was Paul’s special commission by Christ to take the gospel to the Gentiles that such a distinction might no longer exist, that instead of birth heritage being the dividing point, it would be the rebirth that takes place in the follower of Christ. Nevertheless, Paul is taking that term “Gentile” and using it to depict the old life, the old self that characterized the life of the believers before they knew Christ.
The rest of the text is a description of that life. The Gentiles “walk…in the futility of their minds.” “Futility” is the same word translated “vanity” in Ecclesiastes. That vain life in which the Teacher claim all that we do is ultimately meaningless – that is the life of the Gentiles.
Why do the Gentiles walk along a path of meaningless existence? The next phrase tells us: “They are darkened in their understanding.” They cannot see their way clearly as to what life really is about. Why can’t they see their way clearly? They are “alienated from the life of God.” If the Spirit of God is not in them; if the Spirit is not working within them, they cannot understand spiritual truth. Why then don’t they turn to God for enlightenment? “Because of the ignorance that is in them.” They don’t turn to God because they are ignorant of him. “But,” we say, “they don’t have to be ignorant. Surely they have heard of God; even without Scripture, they can see the creation about them and reason that there is a Creator.” That’s a start. If they would consider how there could be a moral law, that would lead them to reason. Maybe if…but the real problem is not lack of opportunity to learn. The Gentiles’ ignorance is “due to their hardness of heart.”
Here is Paul’s fuller treatment of the subject from Romans 1:18-23:
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. 19 For what can be known about God is plain to them, because God has shown it to them. 20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. 21 For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened. 22 Claiming to be wise, they became fools, 23 and exchanged the glory of the immortal God for images resembling mortal man and birds and animals and reptiles.
Mankind is ignorant because mankind is rebellious, which, by the way, is a simple principle that every school teacher knows. They know that test scores are only partially related to the intelligence of their students. Their best performers are measured by their desire to learn, not their innate ability. Teachers take delight in helping the students who want to learn, but they struggle to want to help the students who show no interest. Indeed, if the resistance is great enough, teachers will even give such students over to follow their obstinate ways so that their understanding grows ever darker.