Charles Ellicott Commentary Genesis 4:5

"but unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell." — Genesis 4:5 (ASV)

Cain was very wroth. — Hebrew, it burned to Cain exceedingly: that is, his heart was full of hot indignant feelings, because of the preference shown to his younger brother.