Genesis 4

Genesis 4:3-5 (NASB)
3 So it came about in the course of time that Cain brought an offering to the LORD of the fruit of the ground.
4 Abel, on his part also brought of the firstlings of his flock and of their fat portions. And the LORD had regard for Abel and for his offering;
5 but for Cain and for his offering He had no regard. So Cain became very angry and his countenance fell.
8 Cain told Abel his brother. And it came about when they were in the field, that Cain rose up against Abel his brother and killed him.
9 Then the LORD said to Cain, “Where is Abel your brother?” And he said, “I do not know. Am I my brother’s keeper?”