俱舍論記 18.46

18.46

「若於父母至謂餘而殺」者，此下釋誤等無。此正明誤殺無逆，如文可知。故《婆沙》云「由二因緣得無間罪：一起加行、二果究竟。雖起加行，果不究竟，彼不得無間罪。雖果究竟，不起加行，亦不得無間罪。」

Regarding "If with respect to parents [...] killing [them] mistaking them for another": below this explains that in cases of error and so forth, there is none. This directly clarifies that killing by mistake does not incur an anantarya, as is clear from the text. Thus the *Vibhāṣā* states: "One incurs an anantarya offense due to two causes: first, undertaking the preparatory effort; second, the culmination of the fruit. Even if one undertakes the preparatory effort, if the fruit does not culminate, one does not incur the anantarya offense. Even if the fruit culminates, if one did not undertake the preparatory effort, one also does not incur the anantarya offense."