Shabbat Prayers: Shelah ha-Kodesh: Tree of Life
The six days of the week are “Chol,” as in “Chullin” that which is not sanctified. There is Chullin of Impurity, such as non-kosher animals, and Chullin of Purity, such as kosher animals. “Six days you shall work and do all your labor,” the “work” being, “Avodah sh-baleiv,” Service of the Heart; prayer. This is prayer post the Tree of Knowledge of Good and Evil; a world of Purity and Impurity.
However, Shabbat is the time when the Tree of Life rules, and not the Tree of Knowledge. This is why the Sages teach, “Shabbat is not a time of prayer,” meaning the same prayer as during Chol when things can be Holy or Impure. The prayer of Shabbat must not be about our needs in the world of post Tree of Knowledge , but addressing The Tree of Life, the Eternal World, entirely focused on our spiritual aspirations and growth. (Massechet Chullin 86a)