We all have a "Shadow" because we create that shadow by repressing things we don't want to face. Even Jacob, when he fought "god" by the river at night was. imho, fighting his own shadow. And his "shadow" injured him in a manner that most affected Jacob- it injured his leg and that was crucial to Jacob's life as a herder of sheep. Fighting your Shadow always causes you some harm, but it still must be done if one is to progress toward God.

I realize you might disagree, Dan, but it's the clearest explanation I've come up with to explain that story, and others.