"And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the Lord." Genesis 4:1
The first verse in Genesis Chapter Four is about Cain, not about "Cain and Abel." So, let's talk about Cain.
Cain was the result of Adam knowing his wife Eve in the Biblical sense; they really KNEW each other. They were intimate, they were physically and emotionally involved with each other. Cain was the fruit of their love. He looked just like his father Adam. Eve declared that Cain was "a man child." Cain was the very first baby ever born on earth and in the universe. Cain was the first human-being to ever have a belly button! He was unique. Cain did not need Abel to complete him, nor was he "part of a pair." Cain was whole in and of himself. Surely, he relished in the love and admiration that he received from both his parents. Cain was a first-born and had all the qualities of a first-born child, even more so after Abel came along.
Adam was also a "first-born" in that he was the very first human-being created, made in the image of God, by God's own two hands. God spoke the world into existence, but, when he made Adam, God got down on the ground, got his hands dirty, got intimately involved with the dust of the ground, humbled himself even. Then being face to face with Adam, breathed into his nostrils the breath of life. Adam "became a living soul," (Gen 2:7). Which brings us to another "S" word in the Bible: soul.
Just as Cain looked like his father Adam, so Adam looked like God, until Adam sinned. Then his resemblance to God was marred. Cain looked like his father Adam until he sinned, too. Surely, murdering another human-being, his own younger brother Abel, turned Cain into an unrecognizable "grotesque creature," if he even faintly resembled his father anymore.
Who do you and I resemble?
~dkg