Then Adam had intercourse with his wife, and she became pregnant. She bore a son and said, "By the Lord's help I have gotten a son." So she named him Cain.
References for Genesis 4:1
Later she gave birth to another son, Abel. Abel became a shepherd, but Cain was a farmer.
After some time Cain brought some of his harvest and gave it as an offering to the Lord.
Then Abel brought the first lamb born to one of his sheep, killed it, and gave the best parts of it as an offering. The Lord was pleased with Abel and his offering, 1
References for Genesis 4:4
but he rejected Cain and his offering. Cain became furious, and he scowled in anger.
Then the Lord said to Cain, "Why are you angry? Why that scowl on your face?