The best analogy that I can come up with to help us understand sin is that of addiction. It doesn’t matter if it is an addiction to alcohol, drugs, food, television, what ever is in a person’s life that they can’t put down.
That’s what sin does in our lives. Sin is an addiction. Our bodies, our flesh as Paul says, crave sin. Our minds say no, it’s not good for us, it takes us out of God’s will and into our own, but our body says do it and just like the addict, we can’t say no unless and until we make our bodies obey our minds.