Genesis 4:4-6

4:4 But Abel brought some of the firstborn of his flock – even the fattest of them. And the Lord was pleased with Abel and his offering, 4:5 but with Cain and his offering he was not pleased. So Cain became very angry, and his expression was downcast.

4:6 Then the Lord said to Cain, “Why are you angry, and why is your expression downcast?