大毘盧遮那成佛經疏 17.25

17.25

次第二月住於水輪，其輪圓而白色。自想身在中，如上方便手作蓮華印，二地二空聚為臺，餘三指開敷，令火風稍合相並，即前觀音印也。觀其身作嚩字，色白，亦以白真言為出入息。問：為觀尊va字耶？為本所持種子作白色耶？是月結蓮花印。於二月中但服水而已，餘皆不食。所謂服水者，但以此真言水入息白乳之字為食也。行者若相應時自得法味持，不復有他食想，但法喜味而充滿身耳。嚴備，謂於中坐也，爾時但觀此字，不觀本尊像也。

Next, in the second month, one abides in the water circle. The circle is round and white. One visualizes oneself within it, using the upāya as above, with the hands forming the lotus mudrā: both earth [little] fingers and both space [thumb] fingers are joined to form the platform, the remaining three pairs of fingers blossom open, and the fire [middle] and wind [index] fingers are brought slightly together side by side—this is the Avalokiteśvara mudrā mentioned before. One visualizes one's body as the syllable VA, white in color, also taking the white mantra as the in-and-out breath. Question: Does one visualize the syllable VA of the deity, or does one make the originally recited bīja white in color? In this month, form the lotus mudrā. During the second month, consume only water and nothing else. So-called consuming water means taking only this mantra-water of the inhaled syllable of white milk as nourishment. When the practitioner resonates with this, he naturally attains the sustaining power of the taste of Dharma and no longer thinks of other food; the taste of Dharma-joy simply fills his body. 'Equipped' means sitting within it; at that time, one visualizes only this syllable, not the image of the deity.