Do not lie to one another, seeing that you have put off the old self with its practices and have put on the new self, which is being renewed in knowledge after the image of its creator. Here there is not Greek and Jew, circumcised and uncircumcised, barbarian, Scythian, slave, free; but Christ is all, and in all.
Colossians 3:9-11 (ESV)
Our new identity in Christ establishes a new way of life.
We are not called to change our "old nature" because it has been replaced with a new one. This new nature is the very life of the His Spirit working in and through us to glorify Christ and draw people to Him. He will refashion and renew our mind so that it thinks and acts like Christ.
Renewing our mind opens us to see opportunities and possibilities of ushering the Kingdom of God into the world. We may be in the world, but we no longer act like it. Like Jesus, we have been given the incarnational mission and ministry to transform people and places.
How do we do it?
According to the Apostle Paul, the Spirit of Christ lives within every believer, regardless of race, gender, or status. While we still retain our cultural identity and heritage, they no longer define us. There is no racial prejudice or ethnic pride in the Kingdom. Thus, we can welcome and see each other and others through God's eyes and respond to them with love and kindness. This allows us to speak the truth in love and not tell lies that will hurt our neighbors and divide people.