VI. .KMndogya-Upanishad VIII. 13 :

' I go from A$yama, the black (the moon), to the /Sabala. the speckled (the sun), and from the speckled to the black. Like a horse shaking his hairs (I shake off) evil, like the moon, freeing himself from the mouth of Rahu, having shaken off the body, I go purified in mind to the eternal world of Brahman V