What was wrong with Cain’s sacrifice in Genesis 4? The honest answer is that we don’t know for sure. We are told what Cain and Abel sacrificed, and we are told that God accepted Abel’s and rejected Cain’s. What we don’t know is whether God had given any commands about sacrifice, and if so, what they were. Later reflection in the Bible provides few clues.
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. Hebrews 11:4, ESV
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. 1 John 3:12, ESV
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. Jude 11, ESV
Some have speculated that the problem was that Cain didn’t offer an animal sacrifice, but even under the law there were grain offerings, and we aren’t given enough information to know if this is the problem. Josephus speculated:
They had resolved to sacrifice to God. Now Cain brought the fruits of the earth, and of his husbandry; but Abel brought milk, and the firstfruits of his flocks; but God was more delighted with the latter oblation, when he was honored with what grew naturally of its own accord, than he was with what was the invention of a covetous man, and gotten by forcing the ground… Josephus, Antiquities 1.54.
Somehow, I don’t buy his explanation, but it illustrates that speculation could be endless. Maybe it was a matter of his heart. Maybe it was in the kind or quality of his sacrifice. Maybe it was both. What is important for us to know is that Cain could have pleased God but didn’t.
What was the mark of Cain? The honest answer is we don’t know. The mark served its purpose in sparing Cain from vengeance, but there is no reason for us to assume that a mark on Cain would have been passed on to his descendants. In fact, that would seem to counter its purpose. I’m old enough to have even heard some racist interpretations of the mark of Cain. Such speculation really comes to a dead end when we realize that after the flood, humanity traced its genealogy through Noah back to Seth not to Cain. Racism is evil, for we are all one in Adam, and we can all be one in the Second Adam – Jesus Christ.