You have been made new
Central to our understanding of what it means to follow Jesus is an understanding that when we believed the gospel and placed our faith in Christ, we were made new. In the gospel of John, Jesus teaches Nicodemus that unless you have been born again (new life), you cannot see the Kingdom. In Ephesians, Paul extends the "new life" paradigm.
"And you were dead in the trespasses and sins in which you once walked, following the course of this world... But God, being rich in mercy, because of the great love with which he loved us, even when we were dead in our trespasses, made us alive together with Christ [new life] - by grace you have been saved (Ephesians 2:1-2, 4-5 ESV)."
Our new life is not only something we should come to understand as a Biblical reality, but also provides a foundation to catalyze a new way of life. Because we have been made new, there is a new way to be human.
Put on the new self
In multiple of Paul's letters, he calls his audience to a new way of living. He does not just dole out commands intending to fill up a task list for the believer to follow. The exhortation Paul commonly gives is grounded in an understanding of our new life.
For example, in the book of Colossians, Paul spends much of the first two chapters reminding his Colossian audience of the new life they have in Christ. He begins chapter three with the words "if then."
"If then you have been raised with Christ... For you have died, and your life is hidden with Christ in God (Colossians 13:1,3 ESV)."
He begins chapter three by grounding his exhortation in the reality of our new life. He goes on to explain that we should put to death the former behaviors that were consistent with our old self (Colossains 3:5-11). Then he calls us to live a life that is consistent with our new life in Christ. He tells us to "put on" certain characteristics. As men and women who have been made new, we are called to "put on" certain qualities, such as compassionate hearts, kindness, etc. We are to clothe ourselves in the qualities of a person who has been made new.
Live consistent with who you are
Paul is telling us to act in a way that is consistent with the new life we have in Christ. We are no longer the people we used to be. We have been made new and have put aside those former ways, we must walk in them no longer.
Oak trees produce a certain kind of leaf, and grow in a certain kind of way. When you walk along a path and hear leaves crunching under your feet, feel the reprieve of the warm sun under the shade and see acorns strewn about the ground, you know you are in the presence of an oak. Leaves, shade and acorns are the product of a certain type of tree. An oak tree won't drop a maple leaf. It won't produce an apple or orange. It is an oak tree and by its very nature will create a certain type of leaf, grow in a certain way and produce acorns.
As a follower of Jesus, we have been changed. We have been born again. As a result, our nature should produce certain traits in us and walking in sin is no longer consistent with who we are. That doesn't mean we won't still struggle with sin, but Paul is telling us that because of Jesus in our life, there is a new way to be human. He is calling us to live in a way that is consistent with who we already are in Christ. We don't live in a certain way to gain the love of Jesus or so that Jesus will gracious enough to change us, but because we have already been loved by Jesus and changed by Jesus through our new birth.