Body and soul: Their relationship
Here, Benjamin Wiker provides a working definition of the relationship between the body and the soul, by the distressing route of ... vice:
We are, to repeat, a real unity of body and soul. Consequently, what we do with either our body or our soul affects both our body and our soul. We become what we do; we are what we have done. Repeated sinful actions literally reform our body and soul according to the sin, so that the actions come to define our very nature by becoming second nature.Hat tip: The Sheepcat
The development of this second nature is called a habit, and since it is destructive, a bad habit, or more compactly, a vice. As the vice becomes more engrained, we increasingly lose our freedom, our power, to act well. The vice then defines our entire being, both body and soul.
To put it in St. Augustine's concise terms, sin is its own punishment.
Thus, a woman who gambles becomes a gambler, a human being entirely defined by a particular kind of self destructive activity that has become her second nature. A man who views internet porn becomes a creature who can do nothing else, who thinks about nothing else, who is entirely defined by this self- and other-destructive activity, body and soul, mind and heart, eyes, fingers, and brain. What they originally chose to do, and what earlier on they could have much more easily chosen not to do, now becomes the master who ruthlessly in-habits them, changing every aspect of their intimate soul-body union.