法華義疏 1.136

1.136

佛有三義：一者、自覺異彼凡夫；二者、覺他異彼二乘；三者、覺道圓滿異彼菩薩。若依由來所判明三種佛，悉非覺義：一者、若言此經辨佛猶是無常，但是覺於無常，未是悟諸法實，故不名為覺。二者、若言此經是覆相明常，既稱隱覆則猶是未覺，不名為佛。三者、若言此經辨佛定是常住，則是常見猶名無明，故不名為覺。今言覺者，覺悟諸法非常非無常，亦復非是四句內外，窮了法實故名為覺。

There are three meanings of "Buddha":
First, self-enlightenment, differing from ordinary beings.
Second, enlightening others, differing from the two vehicles.
Third, the perfection of the path of enlightenment, differing from the bodhisattvas.
If one relies on the distinctions traditionally made regarding the three kinds of Buddha, none are the meaning of enlightenment:
First, if one says that this sūtra distinguishes the Buddha as still impermanent, that is merely being enlightened to impermanence and is not yet awakening to the reality of all phenomena; hence it is not called enlightenment.
Second, if one says that this sūtra conceals the marks to clarify permanence, since it is called concealed, he is still not enlightened; he is not called a Buddha.
Third, if one says that this sūtra distinguishes the Buddha as definitely eternally abiding, that is an eternalist view and is still called ignorance; hence it is not called enlightenment.
Now, what is called enlightenment is awakening to all phenomena as neither permanent nor impermanent, and furthermore as neither inside nor outside the four alternatives; thoroughly penetrating the reality of phenomena is called enlightenment.