Which verse says that? It says Cain was the first son I thought, not first offspring? But even if he was the first offspring, throw a femal in there, 1 or 4 years later. 4 years isn't much in the scheme of 100 years. There could have been many females and 100 human when Cain killed Abel.
KJV -And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD.
ASV - And the man knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man with the help of Jehovah
She could have had 30 girls before then...though that many of 1 sex in a row is statistically unlikely. The Bible rarely mentions female in genealogies, so it doesn't mention any females from Enoch to Noah ect. Surely they weran't just having male sons and no female?
Just like the Bible has 'challenges' were Genesis isn't historical ect. Atheism has challenges too.
Moral sense is not a moral compass though......That is the challenge with Atheism... If we were created with a moral sense, we want to do good things....what is good without it being defined? Hitler thought eliminating Jews was good. Some people think world peace is good, and it might be...but in order to attain world peace, we must kill all of those who don't want world peace or who would prevent it from occurring. Do the ends justify the means? And then we would have to have to kill anyone who would attempt to disrupt that world peace, to maintain it would be ugly. What if that person you needed to kill to maintain world peace was defended by a friend, and now you need friends to stop them....and you are at war again, and world peace is over. World peace is impossible in this fallen world. And I am not justifying Hitler by any means, but if you think from his sick mind, he could have been attempting to be doing a great thing, to attain world peace, or if not Hitler, possibly some of the brain washed below him actually thought they were doing a good thing. There are those who (probably not any more) truly ignorant, and believed black people were inferior and less human. If that were the case, they were tainting our awesome human pool and getting rid of them would do the human race a favor.
Atheist claim that we are born with a moral sense (which is arguable) but we have no moral compass. Morality is in the mind us individuals. Sure you could claim that most know that rape and murder is wrong, but what if that person was Hitler, then would it be OK to murder him? Our morals change with no black and white truth. Do you think Hitler was born with a moral sense? What happened to it? What if there are others with that same warped/warp-able moral sense? Can we kill them, or imprison them? The atomic bomb killed tens of thousands to save millions, was that moral? Hitler could have been killing the millions to save the billions (human race). People mean well do bad things all the time.
The law tells us what is truth and is black and white (yet some even attempt to 'interpret' it their own way and kill in the name of). So if something so seemingly black and white is misconstrued, than how much more would the lack of anything be misconstrued.
What if a guy thought he was better than you, but was a moral guy. And since life is unfair, you got a promotion he would have been better suited for, or arguably deserved. Maybe he wouldn't kill you, but within the confines of the 'mass accepted moral goodness' had a vendetta against you and got your fired or stretches some truth and gets your fired? It benefits him, its moral for his goodness.
I can't think of every possible example, but you can't have a moral sense with no moral compass. If the ends justify the means then is anything allowed in the meantime?
Though I don't believe in a moral sense, that is why God gave us the 10 commandments. It wasn't a law necessarily, more of a gauge or a thermometer of our souls. It showed how jacked up we are, and Jesus expands on these later.
It was never about not murdering....though that is bad, it was always about the heart or anger.
It was never about not stealing...though that was bad, it was about why one needs to steal. Does God not provide for us, to you trust Him enough to provide for you so you don't need to steal? Or even to the extent of faith that God will provide for you that you give to the poor and needy.
Though the laws (outside of the 10 commandments) was used to the Israelite's to make them a priesthood or an example of how one should live as a people of God, and to show us that we can't uphold that law no matter how hard we try.
All of the commandments were thermometers to show us how disgusting our hearts really are. Idols, I don't think it the Israelite's who where just brought through a red sea by God, who was a pillar of smoke and cloud and delivered them from Egypt with plagues, was a golden calf. However a golden calf represents strength, as if they can make God who they want God to be. They wanted a strong God, so they made an idol of a strong god. We can't control or define God, I am who I am, that is why we shouldn't make Idols, they can't capture who God is. Don't covet because God will provide for anything you need, so no need to covet, be thankful and content. I could go on...
But the law is good as a guidepath/guidestone, that isn't what gives us our morality either. The only moral thing is God. When we obey the greatest commandment to love Him with all our being, and to love our neighbor as ourselves, that is where morality comes from. We can't not covet apart from God, He is the reason we don't covet, because faith in His provision. We can't not steal apart from God. not just stealing possessions. You could steal someones glory or credit, you can steal someones reputation by spreading lies about them. But when you realize our security is in God, we don't need the accolades of man, God accepts us who we are.
I am not saying I don't violate many of these, I have flesh, and it is difficult. But what helps me not do those things best is when I stay close to God. I don't think it was in this thread but I spoke of a fish out of water will die, so is a fish free to jump out? I am free to murder, but murder will harm me, Freedom is living by design, not by desire. When we follow our design, the Biblical guide-stones, we are free and living what most would call a 'moral' life. But if I do live a moral life, it is not from me, but from God. That way in all things we can boast in God. Why am I not in a wheel chair? Why do I have some level of intelligence? Why do I have a job making all of this money? Some say it was from working hard and picking themselves up by the bootstraps (and there is nothing wrong with working hard). But my beliefs is that God has blessed me with what He blessed me with, and anything I have I owe to Him. My good morality that I might show at times is due to Him.
But the heart is what makes one moral, not your actions. Your actions can be moral in appearance, but it could be selfish to live a life of comfort or a god-like calling to attempt to achieve world peace, or outright immoral.
Those that kill others in the name of God have a moral sense that they are helping God out. They are note, nor are they honoring God nor following His teachings. They also lack faith in the God they claim, that that God can't accomplish this task without that. Though God can chose us to be a tool to accomplish something, I will never say God needs me to get anything done.
Morals are a construct of man. God shined a light on us with the display of the law, or measured our spiritual temperature with the law, but our temperature what the same before we measured it, the thermometer didn't change the temp, it just let it be known. Moral is an attempt of man to make us holy. God is the only one who is holy, that term by definition is set apart (for God). Only God is holy, there are no actions that can make you holy, so we constructed 'moral' as doing good things. The Bible says all of our deeds (good and bad) are like filthy rags apart from God. The only reason we are holy is through the atonement of Jesus, justifying us and making us righteous before God.
So no, I don't think there was any moral sense against incest back then before the law.