Genesis 4:2-8

Then she also gave birth to his brother Abel. Now Abel became a shepherd of flocks, but Cain worked the ground. In the course of time Cain presented some of the land’s produce as an offering to the LORD. And Abel also presented an offering — some of the firstborn of his flock and their fat portions. The LORD had regard for Abel and his offering, but He did not have regard for Cain and his offering. Cain was furious, and he looked despondent. Then the LORD said to Cain, “Why are you furious? And why do you look despondent? If you do what is right, won’t you be accepted? But if you do not do what is right, sin is crouching at the door. Its desire is for you, but you must rule over it.” Cain said to his brother Abel, “Let’s go out to the field.” And while they were in the field, Cain attacked his brother Abel and killed him.