大方廣圓覺修多羅了義經略疏 1.402

1.402

後、明悟則成佛。上且標宗，未為酬問。今顯悟之成佛，方名本起之因。

Second, clarifying that awakening is becoming a buddha. Above, the doctrine was merely indicated, not yet answering the question. Now, revealing that awakening to it is becoming a buddha constitutes what is called the cause of the original beginning.