Frequently we do not leave the past behind. We clasp on to it. We dissect it, and let fears for the future, tempered by the past, unconsciously prevent us from taking up the task eternal.
It is only when we come to total and unconditional "love" of our own darkness that we can know God incarnate in us, loving and understanding us in our totality. Pascal says that no one can love God without knowing their own misery.