The root of the repair — the joining of MaH (gematria 45) and BaN (gematria 52): interrelation and kinship between the Sefirot.
The matkela — the joining of MaH (the Forehead radiation) with BaN (the Eyes radiation) — is the root of the cosmic repair. The Sefirot become Partzufim through this joining via kinship-chains.
Op. 59 opens the World of Repair unit (Op. 59–69) with the foundational claim that anchors the rest of the book: the root of the repair is the joining of MaH and BaN — the matkela balance from Sifra DeTzeniuta. The chapter introduces the kinship-architecture (Father/Mother/Son/Daughter) that becomes the structural form of the named-Partzuf walk.
The new MaH from AK's Forehead (Op. 54) and BaN (the receptive expansion) are the two roots of the cosmic operational level. Their joining is the matkela (balance) — the structural-operational equilibrium that makes everything in the cosmic government's deed-dependent mode possible. The Hebrew term matkela comes from Sifra DeTzeniuta (one of the most concentrated texts of the Zoharic literature). Klach's reader is meant to feel that this principle has been operating in the tradition all along; Klach is now explicating it.
When MaH and BaN join, love is awakened; facing-columns (the three-column structure of yosher) operate with their intermediary architecture (Tiferet between Chesed and Gevurah); the Sefirot, which were operating in their unintegrated post-Nekudim state, become Partzufim through comprehensive kinship-chains. Father (Abba) and Mother (Imma) become the parental Partzufim; Son (Zeir Anpin (Z"A)) and Daughter (Nukva) become the operational pair. The kinship-architecture is what gives the named-Partzuf walk its cosmic-anatomical meaning.
The facing-columns + intermediary architecture is structurally significant. Right column and left column would be in opposition without an intermediary; with Tiferet (the intermediary), the columns face each other in coordinated governance. The matkela is what produces this facing-relation.