俱舍論記 17.157

17.157

「然大德說至如聰慧馬」者，敘異說。故《婆沙》云「大德說言：諸傍生類殺害父、母，於無間罪有得、不得，謂聰慧者得，非聰慧者不得。曾聞有聰慧馬，人貪其種，令與母合。馬後覺知，斷勢而死。」

Regarding "However, the Venerable says: ... like the intelligent horse": this recounts a divergent view. Thus the *Mahāvibhāṣā* states: "The Venerable says: When various animal classes kill their father or mother, regarding the uninterrupted sin, some incur it and some do not; that is, the intelligent ones incur it, while the unintelligent do not. It was once heard that there was an intelligent horse whose breed humans coveted, and they made him mate with his mother. The horse later realized this, severed his own male organ, and died."