大方廣佛華嚴經隨疏演義鈔 37.34

37.34

疏「諸行無常速起滅故」者，釋成盡是有為之義。故《涅槃》云「諸行無常、是生滅法、速起滅故、剎那不住故。」

The commentary's phrase “because conditioned formations are impermanent and swiftly arise and perish” explains and establishes the meaning that exhaustion is the conditioned. Thus the Nirvāṇa Sūtra says: “Conditioned formations are impermanent; they are dharmas of arising and perishing. Because they swiftly arise and perish, they do not abide for a single kṣaṇa.”