Genesis 4:7 WEB

⁵  but he didn't respect Cain and his offering. Cain was very angry, and the expression on his face fell.

⁶  Yahweh said to Cain, 'Why are you angry? Why has the expression of your face fallen?

⁷  If you do well, will it not be lifted up? If you don't do well, sin crouches at the door. Its desire is for you, but you are to rule over it.'

⁸  Cain said to Abel, his brother, 'Let's go into the field.' It happened, when they were in the field, that Cain rose up against Abel, his brother, and killed him.

⁹  Yahweh said to Cain, 'Where is Abel, your brother?' He said, 'I don't know. Am I my brother's keeper?'