大方廣佛華嚴經隨疏演義鈔 79.85

79.85

疏「然約下智不及」下，釋上密義。故《法華》云「我以無數方便種種因緣譬喻言詞演說諸法，是法非思量分別之所能解，唯有諸佛乃能知之。所以者何？諸佛世尊唯以一大事因緣故出現於世。」釋曰：種種說法皆為一乘，眾生不知故，云祕密。「故涅槃」下，引證，亦如前引。

Regarding the commentary's "However, in terms of inferior cognition being unable to reach it": this explains the esoteric meaning above. Therefore, the Lotus Sūtra says: "I, through countless upāyas, various causes and conditions, similes, and words, expound all phenomena; this Dharma cannot be understood by thought and discrimination; only buddhas can know it. For what reason? The buddhas, the World-Honoured Ones, appear in the world solely for one great cause and condition." Explanation: The various expoundings of the Dharma are all for the One Vehicle; because sentient beings do not know this, it is called secret. From "Therefore the Nirvāṇa [Sūtra]" downward, it cites proof, which is also as cited before.