The action of the letters is completed by the musical notes, vowel points and crowns.
Letters alone are insufficient. Their action requires taamim (musical notes), nekudot (vowel points), and tagin (crowns) to be operationally complete.
Op. 19–20 set up the letters and their CHaDaR content. Op. 21 says that the executive set is not the letters alone. The cosmic-operational system requires four levels — letters plus three additional layers — to be complete. The chapter establishes a completion-doctrine that will recur structurally throughout the book.
In Hebrew Bible texts, the consonant-letters carry the basic phonetic identity. But to read the text liturgically, you need additional information: the vowels that modify the consonants, the cantillation marks (musical notes) that determine intonation and phrasing, and the crowns that decorate certain letters with mystical significance. All four together — letters, vowels, notes, crowns — are required for the text to be read aloud.
Klach takes this liturgical fact as cosmologically meaningful. The four levels parallel the four expansions of the Four-Letter Name that Op. 22 will introduce. AV (gematria 72), SaG (gematria 63), MaH (gematria 45), BaN (gematria 52) — the four expansions — correspond to the taamim, nekudot, tagin, and ot-letters at the cosmic-anatomical level.
The completion-doctrine generalises. Every cosmic-operational unit requires multiple levels to be operationally whole. A Sefirah requires Vessel + Mochin + Inner/Encompassing Light (Op. 28–29) — three components, none alone sufficient. A Partzuf requires measure of thickness, measure of height, and binding in Likeness of Man (Op. 70) — three architectural features, all required. The same structural logic applies again at Op. 127 (Tzelem: Inner and Encompassing Mental Powers, both required for complete Mochin).
Op. 22 will explicitly map the four levels of letter/vowel/note/crown onto the four expansions AV/SaG/MaH/BaN — completing the structural correspondence Op. 21 plants.