Despite his deed, god will protects cain: ''and god put a mark on him, so that noone who came upon him would kill him." What do you think this means?
There are a couple of parts to your question; so it's helpful to break it down.
First, no one really knows what the "mark" is that God put on Cain. Some theologians interpret it to be a kind of birthmark on his face that would easily distinguish him from others as the earth became more populated. Personally, I think that it was some type of physical disfigurement that would not change with age or other changes that naturally occur to the human body, making it so Cain could never "outgrow" the penalty of his sin.
In regards to why God put the mark on Cain, the second part of the quote simply means that Cain was not going to be able to escape his guilt or reputation by being killed. This implies that Cain would have rather died then continue on with life knowing that he killed his brother and grieved God. The mark enables Cain to have a figurative form of life imprisonment.
I think that you can see this in a number of different ways. Here are a couple of interpretations:
- God is saying that only he is able to judge the actions of people. He is telling the people that it is not their place to punish Cain, it is only God's place to do that.
- God is saying that there are punishments that are worse than death. He wants Cain to suffer for what he has done. He thinks that, by marking Cain, he will make him suffer because people will know what he has done and will shun him. At the same time, Cain himself will have to live with his guilt. God is thinking that this is a worse punishment than death.