I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me. – Gal 2:20
And I am as loved by God as if I had lived the life Christ lived. So “It is not me that lives, but Christ” is a triumphant statement that, though “we ourselves” are sinners, in Christ we are righteous. Then v.21 comes immediately to say, “Now when I live my life and make my choices and do my work, I do so remembering who I am by faith in Christ, who loved me so much!” The inner dynamic for living the Christian life is right here! Only when I see myself as completely loved and holy in Christ will I have the power to repent with joy, conquer my fears, and obey the one who did all this for me. – Tim Keller, Living the Gospel – Study 4, Paul’s Letter to the Galatians.