俱舍論疏 14.222

14.222

論「又諸聖者至如殺生等」，第三證也。既殺生聖不犯，殺等是性罪。飲酒聖不犯，故亦是性罪。

The treatise says: "Furthermore, noble ones [...] just like killing living beings and so forth." This is the third proof. Since noble ones do not commit killing living beings, killing and the like are natural offenses. Since noble ones do not commit drinking alcohol, it is therefore also a natural offense.