(Rom 1:9) “For God is my witness, whom I serve with my spirit in the gospel of his Son,…” Your soul is the real you, your consciousness. It has been housed in a physical body from the day of your birth. At the moment of salvation, you was given a spiritual body, a living abiding connection with God Who is Spirit. To serve God in the flesh is to do as we will, what we want. To serve God in the spirit is to submit to Him doing what He desires. How can I tell which it is I am doing? Answer: serving in the spirit is always the Lord first, others second, me last.