請觀音經疏闡義鈔 1.106

1.106

「聖觀智觀前人」等者，上觀去聲，下觀平聲。即是意輪觀彼十界身口之機，則可名觀世身、觀世音也。非是聖人用自己身口觀他也，以身口但能現身說法故。然實觀三業之機，彼既正以身口為難，故不云意，但言觀前人身口也。

Regarding "the sage's contemplative wisdom contemplates the person before him" and so on: the upper "guan" is in the falling tone [contemplative], while the lower "guan" is in the level tone [contemplates]. That is, the mental wheel contemplates the capacity of the bodily and vocal [actions] of those ten realms, which may then be called Contemplating the World's Body and Contemplating the World's Sound. It is not that the sage uses his own body and mouth to contemplate others, because body and mouth can only manifest bodies and preach the Dharma. Yet in truth he contemplates the capacity of all three karmic actions; since the other party specifically raised an objection regarding body and mouth, he does not mention the mind, but merely speaks of contemplating the body and mouth of the person before him.