金剛經纂要刊定記 2.203

2.203

廢別下。或曰：「既云耳根發識故聞，合云耳聞。云何經內唯言我聞？」故此釋也。以耳是六根之別，我是一身之總。今廢別耳從其總我，故言我聞。

From 'Setting aside the distinct' downward: Someone might ask: 'Since you say hearing occurs because the ear sense-faculty gives rise to consciousness, it should be called "the ear heard." Why does the sūtra only say "I heard"?' Hence this explanation: Because the ear is a distinct part of the six sense-faculties, while 'I' is the total of the whole body. Now, setting aside the distinct ear and following the total 'I,' it says 'I heard.'