Comentario sobre Levítico 16:26

והמשלח לעזאזל "And he who sends the scapegoat to Azzazel, etc." Who or "what" precisely is the "Azzazel?" We are told in Yuma 67 that it is something "tough and hard." This in turn has given rise to many explanations none of which are satisfactory. My eyes have been opened by kabbalists who are privy to the "370 illuminating lights of the Torah," who have written in the Zohar volume 2 page 157 that the barren desert is the habitat of Samael (Satan). In fact, the reason such a piece of earth is called "desert" is because it is Satan's habitat. An alternate name for this desert is Azzazel; a derivative of that name is עוזא, עזאל. Perhaps the word עזאזל is a composite of עז אזל, "a place where the glory of their existence departed." Alternatively, עזא זל, the site of the force of something base, mean; seeing that Samael is the basest of all spiritual forces, the description would be quite appropriate.

ורחץ את בשרו במים, “and he shall wash his flesh in water.” This was sufficient as his state of ritual defilement does not last longer than until the evening. (Ibn Ezra)