You've heard that expression before right? The one that says, "She was always afraid; scared of her own shadow".
There is truth here. Our shadows scare us. Jung believed our unwanted, disgusting, and most evil parts of ourselves resided in the shadow.
If you've ever felt a tinge of disgust towards someone who was behaving "badly", you're seeing a shadow part. Because these parts of ourselves are so unwanted, we forget that we have them in the first place. However, their ghosts remain and we see them in other people.
The murderer, thief, liar, and cheat reside within all of us. They are our darkest parts. You may think that the answer then is to keep them hidden. Away. Gone. Lost.
What happens when something is left unseen? It does not go away, but can actually grow. It's weeds become unruly and forms an ecosystem all its own.
True freedom from our shadow comes in a counterintuitive form: to embrace, see, and acknowledge its presence. When we shine our light onto our darkness, it illuminates and casts the shadows out. In that form, we can see the truth and fear not what was once unseen.