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).
When we embraced Christ and received him, it was not to continue on in the same futile ways of thinking. If our lives do not differ from the lives of unbelievers, we have not truly learned of Christ. When Christ calls us to himself it is always a call to leave the world, die to self, and live for God. Let us never accept a false gospel which says we can have Jesus as Savior without also having him as Lord. It must be both or neither.
What does it look like, then, to have genuinely “learned Christ”? Paul mentions three things (using three infinitive verbs). Learning Christ means we are renewed in the spirit of our minds (v. 23), we put off the old self (v. 22), and we put on the new (v. 24). These exhortations get to the heart of the New Testament view of sanctification. The moral imperative for the Christian is to “be who you now are.” We are new creations in Christ, so let us turn away from the old ways of the world and live like new people of the Spirit. When we sin, we betray our new identity as sons and daughters of God. Our obedience does not create our holy status but reflects it, honors God by it, and aids others through our expression of it.
Adapted from the Gospel Transformation Bible