Chumash with Rashi for Vayeishev
24. And they took him and cast him into the pit; now the pit was empty there was no water in it.
Rashi: now the pit was empty-there was no water in it: Since it says: “now the pit was empty,” do I not know that there was no water in it? For what purpose did the Torah write,“there was no water in it” ? [To inform us that] there was no water in it, but there were snakes and scorpions in it. [From Shab. 22a, Chag. 3a]
In ruchnious terms snakes and scorpions represent the forces of evil. And water represent the Torah, as it says ein maim elo Torah. This comes to teach us a profound lesson. If there is no Torah in ones mind then you can be sure that evil thoughts will be prevail. If a person is not thinking good positive thoughts proactively then he will not remain a neutral person eventually not good and not holy thoughts will preoccupy his mind.
Evev Yud Tes Kislev 5771.