3 In the course of time Cain brought some of the fruits of the soil as an offering to the Lord. 4 And Abel also brought an offering-fat portions from some of the firstborn of his flock. The Lord looked with favor on Abel and his offering, 5 but on Cain and his offering he did not look with favor. So Cain was very angry, and his face was downcast.

6 Then the Lord said to Cain, "Why are you angry? Why is your face downcast? 7 If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it."

Matthew Henry's Commentary on Genesis 4:3-7

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.