首楞嚴義疏注經 5.147

5.147

雖悟四諦，復了音聲本常，微密圓滿，未曾生滅，唯一覺性。此則了音聲性空，唯如來藏，故云妙音密圓。此經所明圓通法門，唯取實證，則不可約隨相而一解。下文如來勅文殊言：「二十五無學，皆言修習真實圓通，彼等修行實無優劣、前後差別。」故知此文正是入音聲慧法門，了聲實相也。

Although he awakened to the Four Noble Truths, he also understood that sound is fundamentally permanent, subtle and round, never having arisen or ceased, being nothing other than the single awakening-nature. This is understanding that the nature of sound is empty, being nothing other than the tathāgatagarbha; hence he says, 'the wondrous sound being secretly round'. The dharma-door of perfect penetration elucidated in this sūtra takes only actual realization, and cannot be interpreted in one way according to mere characteristics. Below, the Tathāgata commands Mañjuśrī, saying: 'The twenty-five non-learners all say they cultivated genuine perfect penetration; in their cultivation there is truly no superiority or inferiority, no before or after.' Therefore we know that this text is precisely the dharma-door of entering the wisdom of sound, understanding the true mark of sound.