Musar zu Mischlej 26:13

Another factor which diminishes Zeal is great fear and apprehension of what the future may bring so that sometimes one may fear the cold or the heat. Other times mishaps or illnesses. Other times from the wind and so on and so forth. This is what Shlomo, peace be unto him, said: "The lazy one says there is a lion in the way; a lion is among the streets." (Mishlei 26:13).

This is precisely like the verse brought earlier "the lazy man says there is a lion in the way.." (Mishlei 26:13). Our sages, of blessed memory, illustrated, in successive degrees, to what extent unfounded fear can go to cause a person to refrain from good deeds. They said (Midrash Devarim Raba 8:6):

He replies: "I am afraid of the lion on the road" [Mishlei 26:13].