Gen 4:3 In the course of time Cain brought to the LORD an offering of the fruit of the ground,
Gen 4:4 and Abel also brought of the firstborn of his flock and of their fat portions. And the LORD had regard for Abel and his offering,
Gen 4:5 but for Cain and his offering he had no regard. So Cain was very angry, and his face fell.
Gen 4:6 The LORD said to Cain, "Why are you angry, and why has your face fallen?
Gen 4:7 If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. Its desire is for you, but you must rule over it."
The account of Cain and Abel is not just interesting but full of theological lessons. For one thing it proves that everything God said would happened if Adam sinned did happen as Cain, the firstborn of Adam, shows that he was conceived in the image of his fallen father. It also shows us the beginning of all false religions as Cain attempts to approach God on his own terms and by his own works. There are only two religions in the world, works and grace, and Abel comes to God on the basis of another’s work which is grace and Cain comes with the fruit of his own labor which is a religion of works.
As the NT tells us, the spirit of Cain is alive and well today and always has been. Anyone who teaches us to live for ourselves and not the Lord is merely reflecting Cain’s sinful attitude, 1Jn_3:12 We should not be like Cain, who was of the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother's righteous.
Jud_1:11 Woe to them! For they walked in the way of Cain and abandoned themselves for the sake of gain to Balaam's error and perished in Korah's rebellion.
Another way this attitude is seen is in those who tell us that as long as our motives are right then God doesn’t care how we approach or worship him. There are those that say that Cain was rejected because his heart wasn’t right; God didn’t care about his sacrifice. But the NT tells us this is wrong, Heb_11:4 By faith Abel offered to God a more acceptable sacrifice than Cain, through which he was commended as righteous, God commending him by accepting his gifts. And through his faith, though he died, he still speaks.
Certainly Cain’s heart was not right with God but it was the sacrifice he brought that proved it. God discarded his vegetable tray for a couple of reasons:
His sacrifice was not just the works of his hands but grown in the ground that was under a curse. Cain was telling God to accept him for what he has done and the problem was that all the works we do are tainted with our sin. All our works arise from sinful hearts and cannot be seen as righteous before a holy God. Yes, he was acknowledging God and that there was a debt to pay but the payment was totally inappropriate because it was mixed with human effort.
Both Cain and Abel obviously had been told to approach the Lord with the sacrifice of a substitute but Cain wanted to bring something he had done because his heart was full of himself. So both his heart and therefore his sacrifice were rejected by the Lord. And this leads to the second reason God had to reject Cain.
His vegetable tray ruined the OT types of Christ. Every once in a while God makes an object lesson of someone who thinks he could approach God in a way that didn’t point to the finished work of Christ. Moses wasn’t allowed to enter the Promised Land because he struck the Rock a second time when God said to merely speak to it. Christ only had to die for our sins once, peace was made and now we approach the Father through this finished work and we can speak to God because Christ has already been struck by death and gained victory over it.
Nadab and Abihu, sons of Aaron, learned this lesson with their lives. Instead of burning incense on the golden altar with fire that came from the brazen altar they used a common fire. The point is that prayers and service must arise from the sacrifice and anything done that is not based on Christ’s work is unacceptable. Again, God took these types seriously since he was teaching that no one can be justified nor can do any act of worship and service until they have been purified through the blood of Christ. Like Cain, Nadab and Abihu decided they could serve God any way they wanted.
Cain no doubt brought a beautiful sacrifice to the Lord but it was totally inappropriate not only because it was an act of rebellion towards God’s will but it didn’t rely on God’s work but on his own. Had Cain first come to the Lord with a lamb and by such faith been justified then it would have been completely appropriate for him to bring his produce as a sacrifice of praise and thankfulness. But he got the cart before the horse and was rejected. And such religions do the same thing today when they teach that we can be right before God apart from anything other than faith in the finished work of Jesus Christ. And no doubt the churches are full of people putting money in the offering plate thinking that this is earning them brownie points with God instead of getting right with God through the Son and then giving offerings based on what God has done for them in Christ.