大毘盧遮那經供養次第法疏 2.71

2.71

然此真言，以此帝（入）㘑（二字）字為體，上有多聲，即是如如之體，即是本來不生。以不生故，即是諸垢障亦自本來不生。稱此理而修定慧具足，故能降伏三世也。灑淨者，掬水中誦三遍，頭上灑也。具者，三昧耶等也。聖天者，本尊等也。為淨身心利他故，以下入於念誦道場對本尊時。三等者，三密也。限量者，同本尊也。句者，法也。

However, this mantra takes these syllables ti (entering tone) [and] ri (two syllables) as its essence; above it there is the sound ta, which is the essence of suchness, which is ādy-anutpāda. Because it is unproduced, all defilements and hindrances are also naturally unproduced from the beginning. Cultivating the perfection of samādhi and prajñā in accord with this principle, he is thus able to subdue the three worlds. Regarding "sprinkling to purify", one scoops water, recites it three times, and sprinkles it over the head. "Fully possessing" refers to samaya and so forth. "Holy devas" refers to the iṣṭadevatā and so forth. "For the sake of purifying body and mind and benefiting others" refers below to when one enters the bodhimaṇḍa of recitation and faces the iṣṭadevatā. "Three equals" refers to the three mysteries. "Measure" means being identical with the iṣṭadevatā. "Phrase" means phenomenon.