Genesis 4:4-8

4And Abel, he also brought of the firstlings of his flock, and of their fat. And Jehovah looked upon Abel, and on his offering;

5and upon Cain, and on his offering, he did not look. And Cain was very angry, and his countenance fell.

6And Jehovah said to Cain, Why art thou angry, and why is thy countenance fallen?

7If thou doest well, will not [thy countenance] look up [with confidence]? and if thou doest not well, sin lieth at the door; and unto thee [shall be] his desire, and thou shalt rule over him.

8And Cain spoke to Abel his brother, and it came to pass when they were in the field, that Cain rose up against Abel his brother, and slew him.