Now the man had relations with his wife Eve, and she conceived and gave birth to Cain, and she said, "I have gotten a manchild with [the help of] the LORD."
Again, she gave birth to his brother Abel. And Abel was a keeper of flocks, but Cain was a tiller of the ground.
So it came about in the course of time that Cain brought an offering to the LORD of the fruit of the ground.
Abel, on his part also brought of the firstlings of his flock and of their fat portions. And the LORD had regard for Abel and for his offering;
but for Cain and for his offering He had no regard. So Cain became very angry and his countenance fell.
Then the LORD said to Cain, "Why are you angry? And why has your countenance fallen?
"If you do well, will not [your countenance] be lifted up? And if you do not do well, sin is crouching at the door; and its desire is for you, but you must master it."
Cain told Abel his brother. And it came about when they were in the field, that Cain rose up against Abel his brother and killed him.
[Gen 4:1-8 NASB]