肇論新疏 2.424

2.424

夫言迹（象）之興，異途之所由生也。而言有所不言、迹有所不迹。是以善言言者，求言所不能言；善迹迹者，尋迹所不能迹。

Indeed, the arising of words and traces (images) is that from which divergent paths come forth. Yet words have that which is not spoken, and traces have that which is not traced. Therefore, those who are skilled at speaking of words seek what words cannot speak; those who are skilled at tracing traces seek what traces cannot trace.