Page 78 - BERESHIT

The offering of Kayin was of inferior quality. Kayin reasoned that Hashem
has no need for the offering itself. Hence the gesture should be good
enough. Hevel went one step further and gave the finest he had. His
offering came from the great appreciation he felt and was wholehearted.
Thus Hashem accepted his offering.
The source of Kayin’s mistake lay in his obstinacy and refusal to learn
from others. Instead of seeing where he went wrong, he grew angry at
Hevel and killed him. Even afterwards, he didn’t learn from his mistake
and thought that he could fool Hashem.
One should learn to appreciate what Hashem gives us and thank Him for
it. Being obstinate can sometimes lead one away from Hashem. One
should learn from all people and every event a lesson on how to serve
Hashem better.

“And it was after a period of time that Kayin
brought an offering to Hashem from the fruits
of the ground. Hevel also brought of the
firstlings of his flock and from their choicest.
Hashem turned to Hevel and to his offering, but
to Kayin and to his offering He did not turn.
This angered Kayin exceedingly and his
countenance fell. And Hashem said to Kayin,
‘Why are you angry and why has your
countenance fallen? Surely if you improve
yourself you will be forgiven. But if you do not
improve yourself, sin crouches at the door. Its