Zohar (01 10b) For while a man is asleep his soul departs from him and an impure spirit comes forth and settles on his hands and defiles them: hence one may not pronounce a blessing without first washing them. Why then, one may ask, is it forbidden, after one has been in a privy, to pronounce a blessing or to read even one word of the Torah, even in the daytime, without washing the hands, although one has not been asleep, so that one's soul did not depart, and one's hands have not been defiled by an evil spirit? Why is it forbidden even if one's hands are quite clean? The answer is: woe to those who pay no heed to the majesty of their Master, and do not realise on what this world is founded. There is in every privy a spirit which feasts on filth and excrement, and settles forthwith on the fingers of a man's hands.’
Zohar (1:53b) When men sleep on their beds at night-time and night spreads her wings over the world, they are having a foretaste of death, and in consequence the unclean spirit is let loose in the world, carrying pollution. In particular it rests upon a man's hands and defiles them, so that when he wakes up and his soul is restored to him, everything which he touches with his hands is rendered unclean. Hence a man should be careful when dressing not to take his garments from a person who has not washed his hands, because in this way he draws upon himself the unclean spirit and becomes defiled. This spirit is authorised to settle in every place where there is the merest trace of the side from which it issues. Hence a man should not let water be poured over his hands by one who has not yet washed his own hands, because in this way he draws on himself the unclean spirit, from contact with the one who pours water over him.
Shabbos (108b) If the hand be put to the eye, let it be cut off; the hand to the nose, let it be cut off: the hand to the mouth, let it be cut off; the hand to the ear, let it be cut off; the hand to the vein opened for blood letting, let it be cut off; the hand to the membrum, let it be cut off; the hand to the anus, let it be cut off; the hand to the vat, let it be cut off: because the unwashed hand leads to blindness, the hand leads to deafness, the hand causes a polypus. It was taught, R. Nathan said: It is a free agent, and insists on remaining on the hands until one washes his hands three times.
Shabbos (109a) It is a free agent, and insists on remaining on the hands until one washes his hands three times. R. Johanan said: Stibium removes cures the Princess, stops the tears, and promotes the growth of the eye-lashes. It was taught likewise, R. Jose said: Stibium removes the Princess, stops the tears, and promotes the growth of the eye-lashes.
