Now the man knew his wife Eve, and she conceived and bore Cain, saying, "I have produced a man with the help of the Lord."
References for Genesis 4:1
Next she bore his brother Abel. Now Abel was a keeper of sheep, and Cain a tiller of the ground.
In the course of time Cain brought to the Lord an offering of the fruit of the ground,
and Abel for his part brought of the firstlings of his flock, their fat portions. And the Lord had regard for Abel and his offering,
but for Cain and his offering he had no regard. So Cain was very angry, and his countenance fell.
The Lord said to Cain, "Why are you angry, and why has your countenance fallen?