A venomous serpent terrorized a certain neighborhood, biting anyone who came near its den. People were dying. The townspeople came to Rabbi Hanina ben Dosa and begged him to do something.
Rabbi Hanina went to the serpent's hole, placed his bare heel over the opening, and waited. The serpent bit him. And died.
The Talmud (Berakhot 33a) records that Rabbi Hanina slung the dead serpent over his shoulder, brought it to the study house, and declared: "See, my children — it is not the serpent that kills. It is sin that kills." The serpent was merely an instrument. If a person is righteous, the serpent has no power over them. If a person has sinned, they need no serpent — God has a thousand other messengers of death.
This incident became the defining story of Rabbi Hanina's extraordinary spiritual status. He was not merely a scholar — he was a man so perfectly aligned with God's will that the natural world could not harm him. Venom that killed ordinary people had no effect on him, because there was no sin in him for the venom to exploit.
The sages drew a practical lesson: fear God, not serpents. Fear sin, not its consequences. The person who focuses on avoiding sin has already neutralized every threat in the natural world. The person who focuses on avoiding threats while ignoring sin has already been bitten — they just do not know it yet.