大方廣佛華嚴經隨疏演義鈔 38.23

38.23

疏「瑜伽四十六」下，二引《大論》證前不生不滅是無常義。正順前經，亦即是生公「常之為無，乃所以無無常，故即不生不滅矣。」即諸行而不可得，故入中道非常非無常也。

In the commentary, from "Yogācārabhūmi, fascicle forty-six" downward: second, it cites the Mahāyāna-abhidharma-samuccaya to verify the preceding point that non-arising and non-ceasing is the meaning of impermanence. This directly accords with the preceding sūtra, and is also Master Sheng's "permanence being non-existent is precisely why there is no impermanence; hence, it is non-arising and non-ceasing." Being unobtainable right within all saṃskāras, one enters the Middle Way: neither permanent nor impermanent.