On the Allegories of the Sacred Laws (2.93-2.97)

but it will be in your hand, that is in the action of a wise man, which, indeed, is true. But it is impossible to take hold of and to master pleasure, unless the hand be first stretched out, that is to say, unless the soul confesses that all actions and all progress is derived from God; and attributes nothing to himself. Accordingly he, when he saw this serpent, decided to flee from it? But he prepared another principle, that of temperance, which is the brazen serpent: that whosoever was bitten by pleasure, when he looked on temperance, might live a real life.

Such a serpent Jacob boasts that Dan is, and he

The soul produces two kinds, the one divine and the other perishable; that which is the better kind it has already conceived, and ends in it; for when the soul was able to confess to God and to yield everything to him, it was not after that capable of receiving any more valuable possession; on this account she ceased to bring forth, after she had borne Judah, the emblem of the disposition of confessing—

and now she begins to form the mortal race—now the mortal race subsists by imbibing; for, like a foundation, the sense of taste is the cause of the duration of animals; but the name Billah, being interpreted, means imbibing. From her was born Dan, which name being interpreted means judgment, for this kind distinguishes between and separates immortal from mortal things, therefore he prays that he may become a workman of temperance. But he will not pray for Judah, for Judah already has the capacity of praying to and pleasing God:

Therefore let Dan, says he, be a serpent in the path.—One path is the soul. For as in the roads one may behold a great variety of living beings, inanimate and animate, irrational and rational, good and bad, slaves and free, young and old, male and female, strangers and natural citizens, sick and healthy, mutilated and perfect; so also in the soul there are motions inanimate, and imperfect, and diseased, and slavish, and female, and innumerable others of the class of evils; and on the other hand, there are motions which are living, and perfect, and masculine, and free, and healthy, and ripe, and virtuous, and genuine, and really legitimate.