Genesis 4:4-7
4 Abel also brought a gift—the best portions of the firstborn lambs from his flock. The Lord accepted Abel and his gift,
Ending off of the other previous verse, Almighty God, had made skins for Adam and Eve by the blood of an animal. They may have taken then and taught it to their sons, that this was something to do when they presented gifts to Yahava. Cain whom was a great cultivator, brought some of his crops to God, and now, in verse 4, we have Moses saying Abel also brought a gift -- but these gifts were not from the crops (which are bloodless) -- these gifts were the best portions of the firstborn lambs from his flock.
A mention here of the firstborn lamb - could be an indication of a picture and shadow of Christ to come far away into the future. And it became a part of the Law, in which the people of God would sacrifice animals, in which would cover the sins of their people for only a year. God's people whom were of Israel did some things that we do not do today, nor would probably really consider ever doing though - we go the store and get meat to eat from the market, though you gotta have hunters out there to bring in the kill (which is not always wrong), murder however is wrong.
Therefore with this gift, and offering - freely of the flocks of lambs was brought the firstborn ones of new births from the sheep that had children. And Yahava accepted his gift.
5 but he did not accept Cain and his gift. This made Cain very angry, and he looked dejected.
However, Yahava did not accept Cain and his gift. Now we do not know why Cain decide not to consult with is brother, perhaps there was a jealousy or something in the heart of him which perhaps he though the gift he would present would be better. Cain could have also asked for some of the flocks perhaps however he decided to go his own way about handling what was learned from his Mother and FAther, and perhaps these bloodless berries, from the crops were done to perhaps change God's mind on having sacrificed animals instead? We just do not know.
However what we see here is Yahava not accepting Cain's gift, and which made Cain very angry, and he look dejected. Which is to look sad, or depressed.
We can see here that in the face of being rejected - it can make a person very angry, and also sad and depressed, and this is something we can learn here with-in this story.
6 “Why are you so angry?” the Lord asked Cain. “Why do you look so dejected?
Yahava, asked Cain - Why are you so angry? Why do you look so depressed?
Notice the care here from the LORD, towards Cain, asking Cain these questions, whats wrong man, what is going on? Even though he did not accept the offer of Cain - he still cared and desired to seek what Cain would say to him.
7 You will be accepted if you do what is right. But if you refuse to do what is right, then watch out! Sin is crouching at the door, eager to control you. But you must subdue it and be its master.”
Yahava said to him, you will be accepted if you do what is right. (He probably was taught about the sacrifices but decided to go his own way about doing it which was not right, not taking what Yahava had done in front of Adam and Eve has to precursor to sacrifice to the LORD, as the LORD sacrificed to clothe Adam and Eve - even after having not been listened to sending them out of the Garden.
God continues going on to say, but if you refuse to do what is right, then watch out! Sin is crouching at the door, eager to control you. But you must subdue it and be its master. Here we have Yahava saying that Cain will be accepted if he does what is right, however... if he refuses to do what is right, to be careful. Sin is crouching at the door, eager to control you.
Yahava says - You must subdue it and be it's master. Notice he doesn't say anything about watch out - Satan is right around the corner crouching at the door.
In the letter of James, he wrote to his audience,
14 Temptation comes from our own desires, which entice us and drag us away. 15 These desires give birth to sinful actions. And when sin is allowed to grow, it gives birth to death.
This relates to what is Yahava is telling Cain, watch out - when temptation comes from our own desires to handle things our own way, they entice us and drag us away to go and do evil, because the sin crouching at the door is now, giving birth to sinful actions, and when sin is allowed to grow in the mind -- it gives birth to death be it (spiritual or physical), or even death to the (mind/will/emotions) soul.
However, Yahava is telling Cain, he has to subdue and master over it - this is before the help of the holy spirit - and we will see Cain give into this desires because of his hatred, anger, saddness, and depression that will continue to eat away at his soul.