金剛般若經疏論纂要 1.195

1.195

無所說者，無別、異，增、減之說，但如證而說，既如其說則無所說，三世佛皆然，故云無異說。故論云「無有一法唯獨如來說，餘佛不說。」無著云：「第一義不可說。」

As for "has nothing preached": there is no preaching that is different, divergent, increasing, or decreasing; he merely speaks in accordance with realization. Since it is spoken in accordance with that, there is nothing preached. This is so for the buddhas of the three times; hence it is called having no divergent teaching. Therefore the commentary says: "There is not a single dharma preached by the Tathāgata alone that other buddhas do not preach." Asaṅga says: "The ultimate truth cannot be explained."