In the last lesson, we saw that Cain, the son of Adam, committed the first murder in history when he slayed his brother Abel in cold blood over a wrong sacrifice. It is apparent that the consequences of the Fall were manifesting themselves, and Cain was about to pay a great price for his violent act. But, as we will see, God's mercy was dispensed to Cain too, in spite of Cain's own issues. Again, one of the things we want to glean from studying Genesis is that God is loving and merciful in the way he deals with humanity, and despite how bad some of our race get, God still reaches out to them. It was a lesson which would not be lost on the earliest disciples of Christ either, as He demonstrated this character as well when his persecutors cruelly tortured Him. It is in this context that the lesson continues, as now Cain has committed the act of violence, and much like his father Adam in Genesis 3, Cain is given a chance to "own" his sin and seek forgiveness. This is where our story continues.
In verse 9, God questions Cain by asking, "Where is your brother?" Cain answers God's question indirectly with a question of his own: "Am I my brother's keeper?" God is all-knowing, and of course He knew already what Cain had done but wanted Cain to confess it himself, which Cain dodges. In response to Cain's avoiding the giving of a straight answer, in verse 10 God chastises Cain by first asking him, "What have you done???" Note also in this passage that God hears the voice of Abel's blood crying from the ground, but not hearing as in an auditory sense - the very essence of life, the life that oozed out of Abel's dying body, resonates in a way that God can discern it. Cain too knows he has done wrong, and at this point is literally "shaking in his boots," for he knew from his father's story what was to come next.
As God is righteous, no crime goes unpunished, and therefore God pronounces a judgment on Cain in verses 11-12. The first part of this judgment we read in verse 11 is that Cain is cursed from the earth. It is vital to note the wording of that, because God is not cursing Cain, but rather is taking from him that which defined him. This "cursing from the earth" is related to Abel's spilled blood, because if Cain were to cultivate the land and grow anything, it would be tainted by spilled blood of a fellow man and therefore deemed unfit for either consumption or as an offering to the Lord. Therefore, the "curse" is that if Cain does try to grow anything, it would be unfruitful. Now, in contrasting Cain's judgment with Adam's in Genesis 3, we see that Cain is prohibited by God to do what God commanded Adam to do, both because of the taint of spilled innocent blood as well as the fact that Cain had a misplaced pride in his own works, and God was taking that away as a punishment. In verse 12, Cain is then compelled to take up a more nomadic existence, becoming what Scripture calls a "fugitive and vagabond." Essentially, Cain's livelihood was lost, and his restless wandering was connected to his survival. As Cain was attached to the land and farming was his life, he is quite upset by this judgment, and says in verse 13 "My punishment is more than I can bear." Having received this blow to his whole way of life, Cain seems a little stunned as he repeats back to God what was just pronounced on him, and in great fear he remarks, "My punishment is more than I can bear." It is at this point God's mercy is displayed too.
Knowing Cain was fearful of his uncertain future, God still loves Cain and vows to protect him. In verse 15, the Scriptural account tells us that God gives Cain a mark, and also a solemn vow that anyone who kills Cain intentionally will receive seven-fold punishment for doing so. The specifics of this "mark of Cain" are not really given in Scripture, but a lot of incorrect speculations have grown up around this question over the centuries. First, the mark has often been associated with a curse, but the problem with that conclusion is the Scriptural record itself - it says in this passage that Cain was given the mark for his protection by God Himself, and that rules out the curse aspect. It should be seen rather as a sign that God has not given up on nor forgotten Cain, and the protection God gives Cain is an expression of divine love and mercy rather than something evil. Secondly, one of the most ludicrous theories about the "mark of Cain" was more widespread in earlier generations than it is now, and it is a racist theory that suggests that the "mark of Cain" was black skin, which to be honest is so stupid that it almost deserves public derision. Therefore, many people who espouse racist viewpoints have tried to say that the whole Black population of the earth is somehow "cursed," and that Cain fathered the Black race because of his curse. But, the theories on this get even sicker - some idiots (and I am being extremely charitable with this term!) have even said that because Cain lacked a wife, he molested an ape and that is where Black people come from. Anyone who would be dumb enough to hold to such racist drivel is rightly condemned a heretic by the Church, and this view is soundly rejected by the Church Fathers as well as most Biblical scholars today. Black people are as human as anyone else, and they are of the same heritage as anyone else. Any attempts to dehumanize them with some twisted theology or hermeneutical isogesis is to be rejected as well. As mentioned, no one knows what kind of mark Cain did receive, but the mark was not a curse but rather an extension and expression of God's mercy. With judgment now pronounced and God's mark upon him, Cain leaves for the "land of Nod," which we are told in the passage is in the east (v. 16). Many speculations about where "Nod" was have been debated and discussed for centuries, as some believe it was in either the area where China is today or in Persia somewhere. I would personally say that I believe the ancient land of "Nod" to be in central Asia, in an area traditionally called Transoxiana just northeast of Persia on the steppelands south of Siberia. That, however, is a personal theory and nothing that I would be dogmatic about. The exact location of Nod is not really relevant to the overall context of Scripture, which as we said is to chronicle God's plan of salvation, and that is why I believe little is mentioned about it.