首楞嚴義疏注經 6.123

6.123

先出所以。觀音所修從三慧入，是眾行之根本也。佛佛演教皆以音聲，機機領悟盡由聞慧，誰人出不由戶，何莫由斯道也。況能於聲塵而亡所得，復根結而歸真際。元明心妙，一多之境融通；本湛覺圓，彼此之名平等。以一切身即一身，故云微妙含容；一身即一切身，故云周遍法界。此即福等之所以也。

First is stated the reason. Avalokiteśvara's cultivation enters from the three wisdoms; this is the root of all practices. Buddhas after buddhas expound the teachings all by means of sound; capacities after capacities attain awakening all by means of the wisdom of hearing. Who can go out except by the door? Why would anyone not follow this path? How much more so when one can lose what is apprehended in the dust of sound, untie the knots of the faculties, and return to the limit of reality! The original clarity of the mind is wondrous, the realms of one and many fuse and penetrate; original limpid awareness is perfect, and the names of self and other are equal. Because all bodies are just the one body, it says 'contained with subtle wonder'; because the one body is just all bodies, it says 'fully pervading the dharmadhātu'. This is precisely the reason their blessings are equal.