Galatians 2.
20 I have been crucified with Christ, it is no longer I who lives, but Christ who lives in me. And the life I now live in the body I live by faith in the Son of God who loved me and gave himself for me.
It is fairly simple to understand that Christ took my place legally, so that I could be acquitted by God.
It is less simple to understand how I can both no longer live and still live at the same time.
I think that one way it makes sense is in terms of love that ‘seeketh not its own’, or ‘does not insist on its own way’ (1 Cor.13). There is a revelation of self and its death that is essential for a disciple. The little tyrant ‘I’ that does seek its own way, is shown up for what it is, and becomes repellent. At the same time, others who project a self life that has not accepted crucifixion also come across as rather repellent.
Another way of putting it is that when Christ really lives in the heart, self has to shrink and die in his presence. Of course it is work in progress, but the initial insight is a watershed, and life follows in a different direction from them on.
When you know that the very Son of God loved you enough to die for you, then there is no need to fight your corner, and you can rely on his resources more than tyrant I’s machinations.
No-longer-I can take it or leave it. Pleasure or hardship, it does not have to grasp at what it wants or cringe at pain. It’s not robotic, just free from tyrant I.