ויבא קין מפרי האדמה מנחה לד'. והבל הביא גם הוא מבכורות צאנו ומחלבהן וישע ד' אל הבל ואל מנחתו. ואל קין ואל מנחתו לא שעה.
There is a fundamental Halachah that is derived from the seemingly unceremonious depiction of the first murder in history. While Kayin was the innovator of the idea of offering a korban, sacrifice, to Hashem, it was Hevel who followed him with a korban of his own, but his was of a different nature. Kayin brought his offering from the inferior portion of his crop, while Hevel brought from the finest of his flock of sheep. We derive from here the concept of hiddur mitzvah, the obligation to beautify and enhance the performance of a mitzvah, as befits the king to…