楞伽阿跋多羅寶經註解 4.146

4.146

言如來非如虛空常等者，《入楞伽》云：「若是常者，應如虛空，不待因成。然自覺聖智乃如來修德究顯，則無是過。」又言譬如虛空，乃顯雙非，離於諸句，故不可言常也。又復若是常者，則是無生，如免馬等角本來無生，則無方便益物之義，故曰「如來非常」。又復更有餘事知如來常者，上云非常非無常，乃據性德圓離。然如來稱性圓證，亦得言常。言無間所得智者，謂究竟始覺無礙智也。

Regarding the statement that the Tathāgata is not permanent like empty space, the Ru Lengqie says: 'If he were permanent, he would be like empty space, not depending on causes to be accomplished. But pratyātmāryajñāna is the ultimate manifestation of the Tathāgata's cultivated virtue, so there is no such fault.' Furthermore, speaking of being like empty space illustrates the double negation: being free from all propositions, it cannot be called permanent. Moreover, if he were permanent, he would be unborn; like the horns of hares and horses, which are originally unborn, there would be no meaning of skillful means benefiting beings; hence it says 'the Tathāgata is not permanent.' As for 'there are other matters through which one knows the Tathāgata is permanent,' the above statement of neither permanent nor impermanent was based on the complete transcendence of nature-virtue (svabhāva-guṇa). Yet when the Tathāgata completely realizes in accord with nature, he may also be spoken of as permanent. 'Wisdom attained without interruption' refers to the unimpeded wisdom of ultimate initial awakening.