The eighth thing to do with the Shabbat meal is ‘מים אחרונים’, ‘Final Water’. At the end of the meal and before the food blessings we wash the fingertips of our hands. The simple explanation is that in older times they used salt with their fingers and that salt could affect the eyes and even to make a person blind. Because of that they used to wash their finger tips with water to remove the negative aspect of the salt from the hands.
The deeper meaning is that water connect to Chassadim and holiness.
“כִּי אֲנִי יְהוָה אֱלֹהֵיכֶם וְהִתְקַדִּשְׁתֶּם וִהְיִיתֶם קְדֹשִׁים כִּי קָדוֹשׁ אָנִי”
“For I am YHVH your God. Consecrate yourselves therefore, and be holy, for I am holy.”
‘Consecrate yourselves’ is for the first water we use to wash our hands before the first blessing of ‘Hamotzi’.
‘and be holy’ is for the final water that is a must because of the negativity attached to the fingers during the meal.
When we pleasure the body with food, the hands become tools for the negative side that has deep roots in the desire for the self of the body. Desire for the self bring the aspect of death on the hands. Before the blessings we must remove that negativity to purify the hands in order to connect to the holiness of the food blessings.
The ninth thing to do is to have a cup for blessing. The cup by itself has ten types of connection. It’s important to wash the cup from the inside and outside and hold it with the right hand of Chessed. The cup should be full, complete because a damaged, broken cup would have the aspect of death.