 The three groups of angels who shout holy, holy, holy[1]
The sages state that there exist three groups of angels who praise Hashem daily. One group of angels says “Holy” one time. Another group recites it twice, “Kadosh, Kadosh.” A third group recites it three times “Kadosh, Kadosh, Kadosh.” Now, what is the meaning of these three groups and the repetition of these statements? So, the first group who says Kadosh one time is expressing a desire to go from below to above and become incorporated within the infinite light of G-d, which is the light of Soveiv Kol Almin. The second group who says Kadosh twice is expressing a desire to draw down the light of G-d from above to below into the world, which is the light of Mimalei Kol Almin. This group desires to draw down G-dliness through the service of Torah study. The third group who says Kadosh three times is expressing a desire to draw down the light of G-d from above to below into the world through the service of Mitzvahs.
[1] Likkutei Torah Emor
