[Avodah] What is the basis of the requirement to wash ones hands upon awakening

[Ben Waxman]

I was recently at a class where the rav discussed Rav Ovadiah's approach 
to kabballah. This question was an example that the rav gave: ROY tz"l 
felt that there is no requirement to wash your hands immediately, just 
do it before tefilla.  In general ROY felt that one can be machmir to an 
opinion in the Zohar, but it isn't a requirement.
Ben

On 9/5/2018 9:15 PM, Professor L. Levine via Avodah wrote:
 > When one sleeps, a ru’ach ra’ah descends upon the body, and when he 
awakens, the ru’ach ra’ah remains on his hands, and is removed by the 
ritual of washing the hands three times (Bais Yosef O.C. 4 from Zohar 
and Mechaber 4:2 with Mishnah Berurah s.k. 8).