大般涅槃經義記 7.174

7.174

下廣合之，有九復次，初三如蛇，次一過蛇，次四如蛇，後一過蛇。

Below, it applies them in detail with nine points: the first three are like snakes; the next one surpasses snakes; the next four are like snakes; the last one surpasses snakes.