Genesis 4:4

²  And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground.

³  And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD.

⁴  And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering:

⁵  But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell.

⁶  And the LORD said unto Cain, Why art thou wroth? and why is thy countenance fallen?