大方廣佛華嚴經隨疏演義鈔 89.18

89.18

疏十六「娑（蘇我切）字」，但有釋義，具云：悟一切法時平等性不可得故。故《智論》云「若聞娑字，知一切法一切種不可得，以薩娑此言一切故。」釋曰：論云一切種智，故《普曜》云「其言智者出智慧不壞音。」《金剛頂》云「一切法諦不可得。」《涅槃》云「娑者，為諸眾生演說正法。」意明種智應時而說，亦不可得。故今經名「降注大雨」也。

Regarding the commentary's "Sixteen: the syllable sa (pronounced su + wo)": it only has an explanation of the meaning, which fully states: "because awakening to the equality of time among all phenomena cannot be apprehended." Therefore the Dazhidulun says: "Hearing the syllable sa, one knows that all aspects of all phenomena cannot be apprehended, because here sarva means all." Explanation: The treatise speaks of the knowledge of all aspects (sarvākārajñatā); hence the Lalitavistara says: "The word 'knowledge' issues the sound of indestructible wisdom." The Vajraśekhara says: "The truth of all phenomena cannot be apprehended." The Mahāparinirvāṇa-sūtra says: "Sa means expounding the true Dharma for sentient beings." The intention is to clarify that the knowledge of all aspects, expounded in accordance with the occasion, also cannot be apprehended. Therefore the present sūtra names it "pouring down great rain."