21 Assuming that you have really heard Him and been taught by Him, as [all] Truth is in Jesus [embodied and personified in Him],22 Strip yourselves of your former nature [put off and discard your old unrenewed self] which characterized your previous manner of life and becomes corrupt through lusts and desires that spring from delusion;23 And be constantly renewed in the spirit of your mind [having a fresh mental and spiritual attitude],24 And put on the new nature (the regenerate self) created in God’s image, [Godlike] in true righteousness and holiness.
Paul tells us to strip ourselves of our former nature which characterized our former life. The previous life becomes corrupt through lusts and desires that spring from delusion.
Be constantly renewed in the spirit of your mind, having a fresh mental and spiritual attitude. If you can be renewed in the spirit of your mind, that means that after you have had a filling, it can go away. Renewal is a bringing back. This is something that must be constantly paid attention to.
Put on the new nature created in God’s image in true righteousness and holiness. We can put on a new nature in God. Paul refers to “a new man” in other translations. To be renewed in the spirit means to be renewed completely, beginning with the mind.