In the simplest terms, Light of the Soul enables the heart to access and be informed by transcendent aspects of the soul.
More technically, it enables the heart chakra to gain perspective and understanding from those parts of the soul which are not restricted by astrological influences. If all of our actions in this lifetime are characterised by the pattern of the heavens when we were born, then we will certainly encounter needless challenges along the way as our own astrological character interacts with the myriad characters of people we know and meet. Light of the Soul brings the heart's understanding on a brief excursion up a lift, into those areas of the psyche that are beyond time and space. In this way we can step out of a pattern, and move forward more fully in accordance with the deeper intentions of the soul.