[The Tathāgata says] “The wisdom of all the buddhas is profound and vast,” causing those in the great assembly to feel respect and openly want to hear what the Tathāgata teaches. It should be known that two kinds of profundity are included in the meaning of the word “profound.” What are these two? 1) The profundity of realization that is expressed as “the wisdom of all the buddhas is profound and vast” and 2) the profundity of the scripture that is expressed as “the gateway to their wisdom is profound and vast.” “Profundity” is the generic characteristic for the former and the individual characteristic for the latter.

The profundity of realization has five types: l) the profundity of the meaning means the profundity that is based on a certain meaning, 2) the profundity of the essence of true reality, 3) the profundity of inner realization, 4) the profundity of the basis, and 5) the profundity of the unsurpassable. What is “profound” is great enlightenment. “Great enlightenment” means the highest, complete enlightenment realized by the tathāgatas. Why is it profound? It is profound because “none of the disciples or self-enlightened buddhas are capable of knowing it.” “Wisdom” means all-encompassing omniscience. Just as it says in the Lotus Sutra:

The wisdom of all the buddhas is profound and vast. The gateway to their wisdom is difficult to ascertain, difficult to apprehend, difficult to know, difficult to understand, and difficult to enter. None of the disciples or self-enlightened buddhas are capable of knowing it.