What is dark clings to what is light and so enhances the brightness of the latter. A luminous thing giving out light must have within itself something that perseveres; otherwise it will in time burn itself out. Everything that gives light is dependent on something to which it clings, in order that it may continue to shine.
Thus the sun and moon cling to heaven, and grain, grass, and trees cling to the earth. So too the twofold clarity of the dedicated man clings to what is right and thereby can shape the world. Human life on earth is conditioned and unfree, and when man recognizes this limitation and makes himself dependent upon the harmonious and beneficent forces of the cosmos, he achieves success.
When you are able to contain both the light and dark together, that is a very enlightening state. It means that you no longer have to choose one experience over another. You do not have to choose love OR hate, blame OR forgiveness, sadness OR joy, anger OR openheartedness. You are no longer polarized; no particular feeling boxes you in and keeps you from the light of true self. You then have access to the full range of human experiences you came into this life to embrace.