Rabbi Shimon Bar Yochai

“ At that time, when the wicked will be erased from the world [RA IY] , prayer ascends in "music" (Niggun) of four kinds, which are the simple song (Shir) Y, double song Y"H, triple song YH"W, and quadruple song YHW"H. In the name of YHW"H ascends the prayer, which is the Shekhinah; Torah in song, Shekhinah in song; Yisrael ascend out of the exile in song. ”

“ Prayer, which is the Shekhinah, ascends and reaches the King during the Ten Zikhronoth, Ten Malkhiyoth and Ten Shofaroth, which are Y Y Y [=30] , and ten factions of angels are awakened and summoned to them and raise them to the ten Sefiroth. ”