Eckhart Tolle explains how guilt ties to your level of consciousness and strengthens your ego identity. When you hold onto guilt from past actions, it becomes part of how you see yourself rather than a signal to change.
We can let go of guilt. As we let go of egoic consciousness, guilt also disappears. Because guilt is on an individual level. It means that you have done something bad in the past. At that time, you didn't know that it was bad. We presume you did it because this was a manifestation of your level of consciousness at that time. Then you become a bit more conscious. Then you look back on their past and say, oh, I did that. And that can easily become develop into a feeling of strong guilt which strengthens the ego. In other words, you transform human unconsciousness as it manifested through you at that time. You transform the human unconsciousness into an identity.