四分律行事鈔資持記 2.1289

2.1289

指五緣者，一是畜生，二作畜生想，三有殺心，四起方便，五命斷。不犯亦同前；但無殺意，錯誤皆開。

In pointing out the five factors: first, it is an animal; second, the notion of it being an animal; third, having the mind to kill; fourth, initiating preparatory action; fifth, the termination of life. The non-offenses are also the same as before: so long as there is no intent to kill, errors and mistakes are all exempt.