大方廣佛華嚴經隨疏演義鈔 21.32

21.32

疏「寂然不動以觀機」者，此言即《周易．繫辭》，具云「夫易，無思也，無為也。寂然不動，感而遂通天下之故。」今借此言也。

Regarding the commentary's phrase “quiescent and unmoving, so as to observe capacities”: these words are from the “Appended Remarks” of the Book of Changes, which says in full: “Now, Change is without thought and without action. Quiescent and unmoving, when stimulated it then penetrates all affairs under heaven.” Here these words are borrowed.