Genesis 4:1-5

And the man knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man with the help of Jehovah. And again she bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground. And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto Jehovah. And Abel, he also brought of the firstlings of his flock and of the fat thereof. And Jehovah had respect unto Abel and to his offering: but unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell.