Colossians 3:10

Paul uses the language of dressing, and it runs for several verses: put off, put on. Clothes are chosen daily, which is the strength of the image and also its limit.

The limit is what this verse addresses. If the new self were only a garment, the change would be entirely external and entirely reversible. So Paul adds a clause that breaks the metaphor: who is being renewed. Present tense, passive, ongoing. The thing you put on is itself alive and changing, which no coat does.

Renewed in knowledge is the phrase that locates the work. Not in behaviour first. Knowledge — and specifically, in the surrounding verses, knowledge of the one whose image is being restored. The renewal happens by way of learning something, and the something is a person.

After the image of his Creator takes the argument back to Genesis, where humanity is made in God's image. Paul is not describing an upgrade to something that was always defective. He is describing a restoration to an original that was damaged.

And the very next verse spells out what the renewed image looks like in practice, and it is not private piety. It is the collapse of the divisions — Greek and Jew, barbarian, slave and free. The new man, in Colossians, is visible mainly in who you will now sit with.