“Let him wash his hands, and pronounce the benediction for the washing of hands.” (Orach Chaiim., § 4.) But out of this short command arise endless distinctions, according to which the act performed is regarded as a valid or invalid fulfilment of the command. כל הנוטל ידיו צריך להזהר בארבעה דברים , במים עצמן שלא יהיו פסולין לנטילת ידים ובשיעור שיהיה בהן רביעית לכל שתי ידים , ובכלי שיהיו המים שנוטלין בהן בכלי , ובכוטל שיהיו המים באין מכח נותן ׃ “Every one who washes his hands must attend to four things. 1st, To the water, that it be not unlawful for the washing of hands. 2d, To the measure, that there be a quartern for the two hands. 3d, To the vessel, that the water, wherewith the washing is performed, be in a vessel. 4th, To the washer, that the water come with force from him that pours.” (Hilchoth Berachoth, vi. 6.) Each of these four limitations requires new explanations and definitions of its own, as for example, there are four things that make water unlawful for the washing of hands; one of these is, if any work be done with it. This necessarily requires fresh definitions of what is and is not work. Then come the directions as to how for the washing is to reach, the position of the hands, whether they are to be held up or down, the drying of the hands. A perfect and accurate knowledge of all these conditions can be attained only by the learned. And after all the care which these things require, the Israelite may after all fall short of Talmudic requirement, for there is still another condition, that involves another host of Rabbinic definitions, the non-observance of which will invalidate the merit of his washing. כל החוצץ בטבילה חוצץ בידים וכו׳ ׃ “Every thing that is an impediment in baptism is an impediment in washing of hands.” (Hilchoth Mikvaoth, xi. 2.) This, of course, leads to a new inquiry, what constitutes an impediment. אלו חוצצין באדם , לפלוף שחוץ לעין , וגלד שחוץ למכה , והדם היבש שעל גבי המכה , והרטיה שעליה , וגלדי צואה שעל בשרו , ובצק או טיט שתחת הצפורן , והמלמולין שעל הגוף היון , וטיט היוצרים וכו׳ ׃