THE ENEMY WITHIN. In case some of you haven't heard, most Christians understand we are faced with three enemies, the "world," the "flesh," and the devil. I didn't put (" ") marks around the devil because he is all too real and their is no 2nd meaning to him, though he does travel with other names and descriptions. Please note about our "enemies": two are outside our bodies, one is within. That's the "flesh."
By the word "flesh" we're not talking about the human body. Sure, we have a imperfect body because of the Fall and the curse on this creation. But the "flesh" that we need to understand is the sinful nature all humans have other than Christ Jesus Himself. Our flesh consists of the lusts, or immoral desires, that takes hold of our minds and hearts. James speaks of how sin entices our flesh, or desires, to act in a sinful way which eventually leads to death - see James 1:13-16.
Our enemy "within" has already been dealt with by Christ on the cross. I like to tell Christians that they were not only sinners by choice but also sinners by nature. A baby is born with a sinful nature that doesn't take too long before it shows itself in the child's choices. Usually this starts with selfishness, stubbornness, greed, and anger. You see this with a child not willing to share, not willing to do what you say, learning to say "no", and having a tantrum when they can't have their own way. This sinful nature continues to manifest itself as we grow older. Either we commit outright crimes against humanity, or we cover up our sins by trying to secretly do things that we think no one sees. Look at Proverbs 5:21 to knock that attempt down! God sees everything, even in the dark, Psalm 139:12.
Now learn this, our "flesh" or sinful nature was put to death on the cross by Christ. He dealt it a "death blow" and it no longer has the power to make us sin. But it is still in our bodies and we need to learn how to deal with it. That study will be dealt with tomorrow. But read Romans 6 to see much of the answer for yourself.