大毘盧遮那成佛經疏 10.52

10.52

此嚩字由謂下有娜字，以此字加於嚩上，以此娜字即是大空之點也。若上縛著點，即次陀字，不須加娜也。此中以畔字為心，是縛義，即金剛縛也。畔陀是遍護之義，是遍一切處以結彼也。遍一切處結彼者，即是結彼法界體也。[SD-E470]一點是遍一切處義。已了達法界金剛之體，結彼令不壞，是結護義也。

This syllable va is because there is a na below; by adding this syllable above va, this syllable na is the dot of great emptiness. If the dot is attached above, it becomes the next syllable dha, with no need to add na. Here, phaṭ is taken as the heart, which has the meaning of binding, namely the vajra-bond. Bandha has the meaning of universal protection, binding them everywhere. Binding them everywhere means binding that essence of the dharmadhātu. The single dot [of the anusvāra] has the meaning of pervading all places. Having comprehended the vajra-essence of the dharmadhātu, binding it so that it is not destroyed is the meaning of sīmābandha.