大般涅槃經義記 7.175

7.175

初三如中，初一復次能害如蛇，言「見毒」等辯喻顯法，見毒喻火，熱增赤現故說為見；觸毒喻蛇，地增身重故名為觸；噓毒喻風，風吹曰噓，亦有經本說為氣毒，其義相似；齧毒喻水，水漬名齧，四大亦可彰法同喻；二性別如蛇；三常害如蛇。

Among the first three that are 'like [snakes]': the first point is being able to harm like snakes—the words 'sight-poison' and so on explain the analogy to reveal the Dharma: sight-poison allegorises fire, because with the increase of heat, redness appears, and thus it is spoken of as sight; touch-poison allegorises earth, because with the increase of earth, the body becomes heavy, and thus it is called touch; breath-poison allegorises wind, because the blowing of wind is called breath (some editions of the sūtra also speak of it as vapor-poison, which has a similar meaning); bite-poison allegorises water, because soaking by water is called biting; the four elements can also manifest the Dharma corresponding to the analogy; second, their natures differ like snakes; third, they constantly harm like snakes.