That, in reference to your former way of life, you are to rid yourselves of the old self, which is being corrupted in accordance with the lusts of deceit, and that you are to be renewed in the spirit of your minds, and to put on the new self, which in the likeness of God has been created in righteousness and holiness of the truth. (NASB)
By the death, burial, and resurrection of Christ, sinful men and women are made into new creatures. They are justified before God and made truly righteous. In this sermon on holiness and sanctification from Ephesians 4:22–24, Dr. Martyn Lloyd-Jones explains that the old self has been crucified with Christ and now lives according to the Spirit of God that dwells in them. However, there is a sense in which the old self is still with Christians. This old self, as Dr. Lloyd-Jones points out, refers to the sinful principle in the body called the flesh. This is why, though they are saved, regenerated, and justified, Christians continually struggle with sin. This struggle is something that will go on throughout the entirety of the Christian life as they battle sin and the flesh. But all believers can rest assured knowing that Christ Jesus will return and bring to completion what He has begun in His people. This should encourage all Christians struggling with sin to put off the old self and flee to Christ Jesus knowing that He cares for and loves them. Christians ought to flee all legalistic moralism, run to Christ, and pursue true holiness as they seek to glorify Him in all they do.
The apostle Paul reminds the Ephesians of what they learned in Christ - to put off the old self and put on the new self.
Putting off the old self and putting on the new self must always be done together. They are two parts of the same action.
Putting off the old self and putting on the new self are once and for all actions. But renewing your mind is a continuous process.
The "old self" refers to our unregenerate nature - what we are by birth and as descendants of Adam. It is corrupted and sinful.
We must put off the old self because it is corrupt and deceitful. The old self belongs to our former way of life before knowing Christ.
Putting off the old self means renouncing and forsaking it. It is like taking off old clothes.
Even though the old self was crucified with Christ, we still need to put it off in our experience by renouncing old habits and ways of living.
We must put off the old self because of what we have become in Christ - new creations. We must live out this new identity.
The old self is the same in all of us - it is what we inherit from Adam due to the Fall. The new self is what we become in Christ through faith.
We must reckon ourselves dead to sin and alive to God. We must not let sin reign in our bodies.
We must yield our members to righteousness and holiness, just as we once yielded them to sin.
We must realize the truth of who we are in Christ - no longer in Adam, but new creations in Christ.
Our old self has been crucified with Christ. We do not need to crucify it ourselves. We only need to put it off in our experience.
Realizing our old self is dead in Christ and we are new creations is strengthening for faith and living the Christian life.