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. 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. They have become callous and have given themselves up to sensuality, greedy to practice every kind of impurity. But that is not the way you learned Christ!— assuming that you have heard about him and were taught in him, as the truth is in Jesus, to put off your old self, which belongs to your former manner of life and is corrupt through deceitful desires, and to be renewed in the spirit of your minds, and to put on the new self, created after the likeness of God in true righteousness and holiness. Ephesians 4:17-24, ESV.
What is a Gentile? In the Old Testament, you were either a Jew, one of the people in covenant with God, or you were not. If you were not a Jew, you were called a Gentile. Paul carries the label Gentile forward into the letter of Ephesians with a similar but slightly altered meaning. To be a Gentile is still to be outside of the covenant people of God. The covenant Paul is referring to now with is the new covenant. Paul is telling the church to quit living like she is outside of the new covenant in Christ.
To live like a Gentile is to live in the dark: not understanding God because your heart is hard against Him. To live like a Gentile is to sell out to sin: not loving God or His righteous ways. This kind of life is incompatible with life in the new covenant. Thus, Paul implores them to quit living like they are still Gentiles.
Those who are in Christ also need to quit this Gentile lifestyle because, as His new covenant people, they have come to Christ through the knowledge of the gospel. This gospel that saves by grace (Ephesians 2:8-10) demands that the saints shed their old corrupt and deceived way of life and that their minds be spiritually renewed in Christ, putting on His image of “righteousness and holiness.”
This goes beyond, “You are saved, so be good.” It means that, because you have been changed, you need to wrap your mind around that reality and start living in it. This is “the way you learned Christ.” Convicted and converted, you have been changed by the Spirit of God. It is time to “put on the new self”: start dressing and walking in a manner that reflects your new identity in Christ.
Living a lie means living in darkness, bondage, and fear. But there is freedom and peace for those who are in Christ and live in light of that truth. I pray that you will experience the joy of that reality today!