The Witness is that which is capable of observing the flow of what is—without interfering with it, commenting on it, or in any way manipulating it. The Witness simply observes the stream of events both inside and outside the mind-body in a creatively detached fashion, since, in fact, the Witness is not exclusively identified with either. In other words, when you realize that your mind and your body can be perceived objectively, you spontaneously realize that they cannot constitute a real subjective self. As Huang Po put it, "Let me remind you, the perceived cannot perceive."
Unfortunately, change and forgiveness do not come easily for me, but ANY willingness to let go inevitably comes from pain; and the desire to change and forgive changes you, and jiggles the spirit, gets to it somehow, to the deepest, hardest, most ruined parts. And then Spirit expands, because that is its nature, and it brings along the body, and finally, the mind.