肇論新疏 3.73

3.73

返本，無餘之名。神道，有餘之號。謂隱現難測曰神，往來所遊曰道。

'Returning to the source' is the name for [nirvāṇa] without remainder. 'Spiritual Way' is the title for [nirvāṇa] with remainder. Being hidden or manifest and hard to fathom is called 'spiritual'; where one roams in coming and going is called the 'Way'.