"I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me."
Being crucified with Christ means in Him, we have shared His crucifixion. It is not by physical crucifixion, but spiritual. It is being one with Christ, which means Christ is living in our bodies and hearts. Our ego is no longer central. When we are crucified with Christ by faith in Him, we are to completely surrender every selfish desire and ambition to the perfect will of God. Self-promotion and self-pleasing desires are the greatest obstacle between man and salvation because it is the nature of man to want to please himself, and this self-recognition is a building block for sin. All sin erupts from the desire to please self, and this is what must be crucified with Christ in surrender to the will of God before salvation can bear fruit.