Genesis 4:4-7

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? 4:7 Is it not true that if you do what is right, you will be fine? But if you do not do what is right, sin is crouching at the door. It desires to dominate you, but you must subdue it.”