"Now Abel kept flocks, and Cain worked the soil. 3 In the course of time Cain brought some of the fruits of the soil as an offering to the LORD. 4 But Abel brought 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?"
I can't tell you what made me think Abel by chance, lucked up and brought the right thing to please God. I had the thought that God was mean...I mean Cain was trying to please him, but he flat out rejected Cain AND his offering. I never understood why, even though I completely understood the Gospel, this was still hidden to me as I had only understood the Gospel, but I don't think I had come to put my faith in Jesus alone. So in my unbelief and lack of knowledge, it was hidden from me.
I have heard the theory that the reason Abel was accepted was he brought the firstborn of his flock, but Cain did not bring his firstfruits. In other words, Cain didn't make God his number 1 priority. He gave him his second best. He didn't do his best so he didn't make the cut. Sorry, Charlie. How absolutely ridiculous is that thinking, especially when you understand the Gospel! How could I have been so utterly stupid to think that Abel lucked up or Abel gave his best, whereas Cain didn't. But now, with my faith firmly in Jesus Christ alone, standing before the Almighty in naked faith in the work of Jesus Christ alone, I can see the true reason for Abel's acceptance. Whilst I used to think it was Abel who gave his best and not Cain, I believe it was the contrary that happened. I believe Cain gave his best and Abel by FAITH, (not his best) offered up an acceptable sacrifice.
You see, the Scriptures are clear that it is only by the shedding of blood that we obtain forgiveness of our sins. Your sins MUST be punished. Your sins MUST be dealt with in justice. Even if I repent and try my best, I have still sinned and those sins must be payed for. I don't care if Cain gave his firstfruits, his best fruit, all his fruit, some of his fruit, any of his fruit! His sins MUST be payed for! The justice of God demands those sins be punished. Without the shedding of blood, there is absolutely no forgiveness of sins.
So Cain, slaving away out in the field, striving to produce some fruit for God, was not accepted. But his brother, Abel, who offered up a LAMB sacrifice was accepted. This is the Gospel. This is no lesson in behavior or exhorting you to give your best for God. This is a lesson of the fact that even if you give your best fruits to God, you will die in your sins if you do not wash your robes in the Blood of the Lamb. Without the shedding of Blood, there is no forgiveness of sins.
So, what did Abel do in order to be accepted by God? He offered up a lamb sacrifice, and God, who knew what this was a picture of, accepted the offering and in accepting this offering, he accepted Abel.
"After this I looked, and behold, a great multitude that no one could number, from every nation, from all tribes and peoples and languages, standing before the throne and before the Lamb, clothed in white robes, with palm branches in their hands, and crying out with a loud voice, "Salvation belongs to our God who sits on the throne, and to the Lamb!"
"Then one of the elders addressed me, saying, "Who are these, clothed in white robes, and from where have they come?" I said to him, "Sir, you know." And he said to me, "These are the ones coming out of the great tribulation. They have washed their robes and made them white in the Blood of the Lamb."