A believer’s unregenerate self – “our old man”. The Greek word for “old” does not refer to something old in years but to something that is worn out and useless. Paul uses the term “body” and “flesh” to refer to sinful propensities that are intertwined with physical weaknesses and pleasures. But the term “flesh” is not equivalent to the physical body, which can be an instrument of holiness.
Commentary from the MacArthur study Bible, notes for Romans 6:6.