Who is Being Replaced in the Exchanged/ Union Life?

 The following is from Knight of Faith, Volume II, a collection of Norman Grubb's personal correspondence.  Toward the end of his long life he wrote:

"I had always thought that when Paul said, 'I am crucified with Christ, nevertheless I live, yet not I, but Christ lives in me,' he meant that it is Christ replacing my unreliable self by Himself.  

"But no.  It is Christ replacing that unreliable Satan 'spirit of error' in my self, because Paul [and John] makes plain my human self was only created a vessel, branch, temple, beautifully made to express its owner and operator, and never itself:  that occupier formerly being that 'spirit of error,' but now 'The Spirit of Truth.'

"As Paul says, 'This life I now live in the flesh I live by the faith of the Son of God who loved me and gave Himself for me.'

"I am free as a self to accept and love myself as a God-made expressor.  No condemnation.  FREE TO BE . . . A complete life!"