大毘盧遮那成佛經疏 20.27

20.27

復次祕密主！說祕密念誦法。亦令一一誦諸真言，佛菩薩等別說。謂隨彼之中取一一，謂各各也。於諸真言中隨取一一，各別而作心念誦。第二作出入息念誦。此二法最為第一相應也。當如是作此二法，是名第一念誦也，勿異此法也。若異此者，於念誦有所闕，支分由不具故也。然以內外相應，分之有四，我先已說也，今下更說也。彼世間者有所攀緣，謂三種中但觀於一字印身，觀之識其本性，如印即字、字即身，無礙而心湛然，是念誦也。若以字作出入息者，知字即真言之體，以此出入資力，名出入息也。然此二中，由出入息有少所攀緣，故當知意念誦即最為上也。字印尊無所分別，作出入息亦得也。此世出世間持誦品，上來一部經意，只為修真言行諸菩薩等作持誦入道之法。而今此品專得其名，當知說一部之要旨也。

"Furthermore, Secret Lord, I shall teach the secret method of recitation." It also causes them to recite the various mantras one by one, spoken separately for the Buddhas, bodhisattvas, and so forth. That is to say, one takes them one by one from among them, meaning individually. From among the various mantras, one takes them one by one according to preference, and individually performs mental recitation. Second, one performs recitation with inhalation and exhalation. These two methods are the foremost yogic connections. "One should perform these two methods in this way; this is called the foremost recitation; do not deviate from this method. If one deviates from this, there will be deficiencies in the recitation, because the auxiliary limbs will not be complete." However, when divided according to internal and external yoga, there are four kinds; I have already explained them earlier, and will now explain them further below. "Those that are mundane have something upon which to rely": that is to say, among the three kinds, one merely visualizes a single syllable, mudrā, and body; visualizing them, one recognizes their original nature—just as the mudrā is the syllable, the syllable is the body, unobstructed and with the mind clear and tranquil, this is recitation. If one performs inhalation and exhalation using the syllable, knowing that the syllable is the essence of the mantra, and with the supporting power of this inhalation and exhalation, it is called [recitation of] inhalation and exhalation. However, between these two, because inhalation and exhalation still involve a slight degree of grasping, one should know that mental recitation is the most supreme. When the syllable, the mudrā, and the deity are without discrimination, performing inhalation and exhalation is also acceptable. In this Chapter on Mundane and Supramundane Recitation, the intent of the entire preceding sūtra is solely to provide bodhisattvas cultivating mantra practice with the method of recitation for entering the Path. And now that this chapter exclusively bears this title, one should know that it expounds the essential purport of the entire work.