3 Sometime later Cain brought some of the produce he’d grown as an offering to the Lord. 4 Abel also brought an offering: the firstborn lambs of his flock, selecting the very best parts to offer. The Lord was pleased with Abel and his offering, 5 but he wasn’t pleased with Cain and his offering, which made Cain very angry and he frowned in annoyance.
6 The Lord said to Cain, "Why are you so angry? Why do you look so annoyed? 7 If you were doing what’s right, then you’d be looking happy.4:7. "Looking happy": literally, "lifted up." In the previous verse, the literal meaning is that Cain’s "face fell." So the opposite would be for his face to be "lifted up," in other words, he would look happy. But if you don’t do what’s right, then sin will be like an animal crouching outside your home, ready to pounce on you. It wants to have you, but you must be the one in control."