חסידות אויף שמואל א 16:16

This is the aspect of washing of the hands in the morning when you wake up from sleep. Because the pure water of this washing is drawn down through the aspect of the revelation of wisdom, which is evoked through prayer in the aspect of justice, as we saw above. For this is the aspect of (Isaiah 11:9) "for the land shall be full of knowledge of the Lord as water covers the sea.", etc. That is the source of the waters for washing upon awakening. Therefore it is necessary to wash the hands specifically, for the essence of strength and might that is necessary to give to the hands so that they may strengthen themselves against 'the heel of the Other Side', in the aspect of 'he grabbed onto Esav's heel.' Specifically, 'hands', because the essence of the rectification is through the faith in the renewal of the word, which is the aspect of hands, the aspect of (Isaiah 48:13) "Even My hand laid the foundation of the earth, and My right hand...", etc. Therefore faith corresponds to the hands, as it is written (Exodus 17:12) "His hands were faith". Because the essence of faith is to believe that Hashem Yisbarach created the world from nothing (literally, 'something from nothing'), which corresponds to 'the hands', as it is written 'Even My hand laid the foundation of the earth, and My right hand...', etc. and to believe in the Torah and the practical commandments which must be done with the hands. Through this, one merits melodies, as seen above, which are the aspect of 'hands', the aspect of (I Samuel 16:16) "he will play with his hand, and it will be good for you." Through all of this we receive the power of Jacob's hands to subdue the heel of Esav, in the aspect of 'he grabbed hold of the heel of Esav'. (Genesis 25:26). His hand, specifically, as explained above. All of these is evoked through the waters of Da'at/Wisdom which is revealed through the prayer of the powerful person, as seen above. In them, we purify our hands after sleep and therefore, specifically the hands are purified, etc., and as explained above.