821. Lulav is the Righteous, NAMELY, YESOD, for the Lulav is like the spinal chord that contains eighteen vertebrae, corresponding to the eighteen shaking movements with the Lulav. And they correspond to the eighteen blessings of the Amidah prayer, and they correspond to the eighteen mentions, NAMELY, THE NAMES OF YUD HEI VAV HEI, in "Ascribe to Hashem, O you mighty" (Tehilim 29:1), and the eighteen times that the Name is mentioned in the reading of Sh'ma. And the Lulav is shaken in six directions: SOUTH, NORTH, EAST, UP, DOWN AND WEST, which makes six, and it is shaken three times in each direction, MAKING a total of eighteen.