I'm digging deep here, well, maybe not deep but desperately. But consider this, these are works made by the hands of men. We are capable of taking stone, wood, ice and many other materials and crafting them into admirable objects of art. Gen. 2:7 tells us that the Lord God formed man of the dust of the ground.... "He formed us", fashioned us, after He had created everything else He formed us....but read carefully and slowly to grasp the reality "and breathed into, the breath of life" and man became a living being.
He spoke all of creation into being, but us He breathed into life. And we were created in His image. An image that He so desires would be clothed in His righteousness.
Didn't really want to post a picture of circumcision here, I'll leave that to your imagination. I thought Kelly did a good depiction of the spiritual circumcision we undergo as we trust in Him in a daily practical life of salvation. "Spiritual circumcision is an internal process that affects the heart by cutting away the whole "body of sins".
I'll take question #4:
Putting to death the habits of my old self? As I replace the old and fill my life with the new that Christ offers me I can truly become a new creature in Christ.