The essence of the Christian faith, is understanding what God the Father has done for us through His Son Jesus Christ. Never forget that, meditate on that, find your joy, your strength in that reality.
A key phrase is what God has already done for us.
As we’ve previously seen Paul has made reference to actions that have taken place in the past. Specifically the completed actions of putting off and putting on. We have put off the old man as Paul describes it and we have put on the new man which Paul described as being created in true righteousness and holiness. These actions took place when God redeemed us.
When God brought us to faith in Christ several wonderful changes immediately take place. One of the changes that God effects in our lives is He removes our old nature and replaces it with a new nature. He puts off the old man and replaces him with the new man which was created in true righteousness and holiness.
It’s imperative that we understand that. Why is that so? Understanding that Paul is referring to completed actions makes the “therefore” of verse 25 make sense.
In other words as a result of what has already happened to you therefore this is not only what you should be able to do, you are now able to do them.
Because the old man has been put off, you can now begin to act like the new man that you truly are.