Verses 20–24 make up one sentence that stands in sharp contrast to the preceding, indicating the basis for a new life that is totally different from that of the unconverted Gentiles.

Learned (Greek manthano) is the very word that is the root of “disciple.” We might therefore paraphrase Paul as saying, When you became disciples (literally, learners), this is not the way you learned. To “learn Christ” is to come to know Him and the way He both exemplified and taught

Teaching is at the heart of church life, and this is a proof-text for Christian education. In the “pillars of the church” listed in Acts 2:42 (apostolic teaching, fellowship, breaking of bread, and prayer), teaching appears first because of its importance for the Christian walk. Today this is neglected in all too many churches, whose leaders seem to think that one sermon on Sunday morning is sufficient to educate their people.

Too many Christians are woefully and even willingly ignorant of the doctrines of the faith. No wonder secularism flourishes!

Paul wants his readers to realize that if they have received Christ and taken up His teaching, His way is totally different from the old way they once knew. A completely new way is called for

Once we recognize the emptiness and hopelessness of the old ways (as seen in vv. 17–19), we should be filled with horror at our terrible choices and throw them far away.

Clothes would rarely be thrown away unless they had become virtually unwearable, and that is the picture here. The old ways are so damaged that they can only be thrown into the trash

It is important to recognize that the mere act of desiring is not a problem. Desiring is but one form of loving. If we were to extinguish all desires we would not be in a position to love God or our neighbor; we would not be able to know God’s love for us. Nevertheless, given the description of the Gentiles’ habits of mind and heart in vv. 17–19, it is not surprising that their desires are generated and driven by deceit rather than the truth that is in Jesus.

You move in the direction of what you put into your mind and what you allow your mind to dwell on. So if you are not what you want to be, then you must begin to think differently. If you are to think differently, you must put into your mind that which you want to become. If you do, the Holy Spirit will use it to change you to become what you want to be. If you don’t, you will never be what you want to be. It all depends on what you put into your mind. This is what it means to be made new in the attitude of your mind

life. Romans 12:2 speaks of being “transformed by the renewing of your mind,” which clearly intimates that the transforming power is the Holy Spirit, who changes us into a harbinger of the new being that will be ours for all eternity. This is a lifelong process in which the Spirit enables us to gain control of our thoughts and proclivities, allowing us to take incremental steps in the direction of curbing our desire to seek earthly pleasures and turning more and more to God. It is in the mind that spiritual growth occurs, and we must embrace the Christlike mindset

But there is another sense in which the Christian puts off the old man and puts on the new man in the present. Doing this is not mere history, then, that can be looked back to. In Paul, it is also exhortation and obligation. We both have put off the old man and must put him off. We do this every time we deny that former life by refusing to live that way.