On 6/10/2018 the Mentionables received this question from Paul McAndrew:
What was the mark placed on Cain?
These are the answers from the team.
This answer is from Mentionables Network Member Randy Hroziencik. For the answer from Joel Furches, scroll below.
Great question, as always, but this is one of those fun questions that can only result in speculation regarding an answer...so I can't really answer this one. Some people may try to tie in the mark of Cain with some of the end-times physical marks on the body, but I do not believe we can definitively do this. For all we know, the mark may not even have been physical, although I suspect that, like most marks, it was. Perhaps the real reason that Cain's mark is not described is because the important thing is that God put this mark on Cain so that he would have to endure life as a fugitive - his punishment for taking the life of a godly follower of the Creator.
This answer is from Mentionables Team Member, Joel Furches
There is, of course, no physical description of the mark in scripture. Whatever it looked like (or didn't), it was a "mark" in the same sense as a bounty or warrent. That is to say, Cain now had a reputation among the general populace. Given the vanishingly small population of the time, this wasn't terribly difficult. The immediate "mark" or reputation was the one about which Cain was concerned: that he was branded as a murderer.
At some level, Cain understood the "life-for-a-life" principle of justice, and was more frightened by the possibility that someone might seek justice in ending his life.
Most people associate "The Mark of Cain" with his curse. In fact, the "mark" was an act of grace and mercy on the part of God. God's grace extended to this fratricidal fugitive: somehow God made it general knowledge that Cain's life was under his protection. In fact, God gave a very specific retributive rule: he who takes Cain's life would suffer sevenfold revenge.
We know that this general rule was understood by the populace, because 5 generations later, Cain's great-great-great grandson referenced this law when he, too, killed a man. Given that Lamech expected the same kind of protection on his life as his grandfather had received for the act of murder, it is at least possible that Lamech understood that the "mark" as a rule or reputation, rather than a physical marking.
It is hard to imagine a physical mark which would convey the specific message, "he who murders this man will suffer a sevenfold curse." Whereas a rule passed down by God would be more generally recognized.