The “old self” that St. Paul refers to has often been limited just to sinfulness. But it has a much broader application than that, I think. The “old self” is the brain-governed self. It’s evolutionary instincts and behaviors aren’t ever going to be motivated by faith and compassion, by something that can’t be physically seen, something that can’t be explained in the context of natural events.
Referring to religious faith and spirituality, Martin Luther wrote, “The knowledge of God is impressed upon the mind of every man by God” (Otto139). His Spirit, moving in our heart and imaging in our consciousness, is what fosters our faith and sustains our believing. When we open ourselves to him, the Saviour at our side meets the Christ spirit in our hearts and lights up a “new self,” a whole new individuality of purpose. We are, as St. Paul wrote, “renewed in the spirit of [our]minds” (NRSV Eph. 4:22-24). http://yieldingtochristianity.com/?attachment_id=548