Granted, Abel was an insufferable pious twit, but that doesn't mean he deserved to die. Although, it does make for good comedy!
"Am I my brother's keeper", found in Genesis 4:9
is one of the most memorable quotes from the bible. The phrase, and
variations thereof, have since become the title of books, poems,
television shows, movies, songs, albums, bands, comic books, plays,
even computer software.
In the Qur'an (yes, the story of
Cain and Abel is in the Qur'an as well), God sends down a raven to
start burying Abel, and Cain gets all pissy because he didn't know how
to bury his brother. That doesn't make much sense, but who ever
expected holy books to make sense?