大方廣圓覺修多羅了義經略疏 2.130

2.130

"Encountering the superior teaching, all achieve it" explains that there is no distinct, determinate nature. Inversely, it clarifies that if one does not encounter superior conditions, one achieves the small [vehicle] in accordance with what is heard; that the text lacks this is an abbreviation. Because of this, it is called the indeterminate nature; therefore sudden and gradual were indicated above.