Venom of Serpent

The episode of Cain and Abel has various ways of explaining how it was possible for one brother to murder the other.

On a more simplistic level, Abel was the one who gave a sacrifice to Hashem generously. Cain was the farmer who was not as generous. When Hashem received the offering of Abel, out of jealousy, Cain murdered his brother in a deceitful manner.

The Alshich explains the story a little bit differently. He spoke of the זיהום, or pollution that came from the serpent. Cain was inherently far more evil than his brother, Abel.

This evil that possessed him, made him act wrongly towards his brother.

This impurity existed for many generations until Yakov Avinu. He was the twenty-third generation from Adam. Yakov was the first to have all righteous offspring. Avraham had Yishmael, and Yitzchak fathered Eisav. The pollution from the snake and its influence had ended.

This allowed the Jewish nation to be formed. The twelve righteous sons of Yakov, grew to a family of seventy. And the seventy grew to 600,000, when the Jewish people left Egypt.

Evil is something very real in this world. It was created by Hashem Himself to test us. It is our job to remove evil from our midst. Eventually, in Messianic times, evil and the pollution of the serpent, will be eradicated forever.