2 Again she gave birth, to Cain’s brother Abel. Abel was a keeper of sheep, but Cain was a tiller of the ground.
3 As time passed, it happened that Cain brought an offering to Yahweh from the fruit of the ground. 4 Abel also brought some of the firstborn of his flock and of its fat. Yahweh respected Abel and his offering, 5 but he didn’t respect Cain and his offering. Cain was very angry, and the expression on his face fell.
Matthew Henry's Commentary on Genesis 4:2-5
Commentary on Genesis 4:1-7
(Read Genesis 4:1-7)
When Cain was born, Eve said, I have gotten a man from the Lord. Perhaps she thought that this was the promised seed. If so, she was wofully disappointed. Abel signifies vanity: when she thought she had the promised seed in Cain, whose name signifies possession, she was so taken up with him that another son was as vanity to her. Observe, each son had a calling. It is the will of God for every one to have something to do in this world. Parents ought to bring up their children to work. Give them a Bible and a calling, said good Mr. Dod, and God be with them. We may believe that God commanded Adam, after the fall, to shed the blood of innocent animals, and after their death to burn part or the whole of their bodies by fire. Thus that punishment which sinners deserve, even the death of the body, and the wrath of God, of which fire is a well-known emblem, and also the sufferings of Christ, were prefigured. Observe that the religious worship of God is no new invention. It was from the beginning; it is the good old way, Revelation 3:20. And those well deserve to perish in their sins, that will not go to the door to ask for the benefit of this sin-offering. God's acceptance of Abel's offering did not change the birthright, and make it his; why then should Cain be so angry? Sinful heats and disquiets vanish before a strict and fair inquiry into the cause.