Genesis 4:13

And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD.

And she again 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 the LORD.

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: