“I have been crucified with Christ;
it is no longer I who live, but Christ lives in me.”
This is the beginning point of our identification: crucifixion with Christ. Here Paul tells us the secret of what it means to be a disciple. A Christian is not someone who believes certain things about Jesus and tries to live a good life. A Christian is someone who is crucified with Christ and has no life of his own.
“Not I, but Christ” is not just the secret of living the Christian life, it is the goal and the end result of all God’s dealings with us along the lines of discipleship. He must increase. I must decrease. Follow this process out to its inevitable, irresistible conclusion and you see that eventually there is none of me; it is all of Him in me.
Source: Embrace the Cross by Chip Brogden