大方廣圓覺修多羅了義經略疏 1.271

1.271

然此正宗中諸菩薩等與佛問答，發揚本意，欲顯圓覺，但緣節節過患未盡，義意未圓、收機未普，故表法菩薩未標圓覺之名。今有三意得名圓覺：一前雖病盡理圓，仍恐下根難入，此又曲開方便三期道場，即上、中、下機普歸圓覺；二由前節級行解已圓，至此名為證極，證極之境更無別體，唯是圓覺；三最初標指圓覺為陀羅尼門者，從本起末，今顯義已周，還至圓覺者，攝末歸本，表此三意，故當此門。

Now, the various bodhisattvas and others in this central part question and answer with the Buddha, developing the original intention in order to reveal perfect enlightenment; however, because defects were not yet exhausted stage by stage, the doctrine was not yet complete, and the capacities gathered were not yet universal, the bodhisattvas symbolizing the Dharma had not yet been designated with the name 'Perfect Enlightenment'. Now there are three meanings for obtaining the name Perfect Enlightenment: First, although previously defects were exhausted and principle was rounded, there was still fear that those of inferior capacities would find it difficult to enter; here, expedients of three periods of the place of practice are accommodatingly opened up, so that superior, middling, and inferior capacities universally return to perfect enlightenment. Second, because the practice and understanding across the preceding stages have already been rounded, arriving here is called the ultimate realization, and the realm of ultimate realization has no separate essence other than perfect enlightenment. Third, initially pointing to perfect enlightenment as the dhāraṇī door was giving rise to branches from the root; now that the revelation of the doctrine is complete, returning to perfect enlightenment gathers the branches back to the root. Symbolizing these three meanings, it therefore falls to this section.