Still incest...? Still not adding up, biologically, like SG pointed out.
Abraham and Sarai, marries his half sister? (Gen 12:29)
[ The Torah, states it may have been his niece, they explain that a man often refers to his relative as sister (Midrash HaGodol)]
Biblically who would be more closer together than Adam and Eve? they are of th very same flesh and blood.... yet all humanity comes from them. Back than God provided a way to procreate.. even after the flood, there were only eight persons in the world
Pe 3:20 "God's patience waited in the days of Noah, during the building of the ark, in which a few, that is, eight persons, were saved through water."
There is more to Cain than the slaying of his brother,Abel. Cain represents the world, who had no problem with his sin, only felt pity for himself in the consequence of his sin, and did not seek forgiveness from God.
Cain moves out from the presence of the LORD, (Gen 4:16), establishes his own civilization in Nod, that is apart from God altogether, and the children of Cain establish a Godless civilization.
From the Chumash: Gen 4:17 commentary,
The torah calls him 'city-builder' cut off from the earth, from God and from his own felloew men, Cain was left with only his own intelligence and talent, which he utilized to build cities. Urban life, unlike rural life, cultivates
Cain pleads for mercy of his punishment, God had given Cain a second chance and promises him not to execute punishment for seven generations. He is eventually killled by
Lamech of his 6th generation at the guidance of Lamech's son Tublal-cain (From the Chumash, Gen 4:23,24)
Commentary:
http://www.blueletterbible.org/commentaries/comm_view.cfm?AuthorID=2&contentID=7324&commInfo=31&topic=Genesis&ar=Gen_4_17
a. And Cain knew his wife: We don’t know where did Cain got his wife. Genesis 5:4 says Adam had several sons and daughters. Cain obviously married his sister.
Though marrying a sister was against the law of God according to Leviticus 18:9; 18:11; 20:17, and Deuteronomy 27:22 (which even prohibits the marrying of a half-sister), this was long before God spoke that law to Moses and the world.
i. Here, necessity demanded that Adam’s sons marry his daughters. And at this point, the “gene pool” of humanity was pure enough to allow close marriage without harm of inbreeding. But as a stream can get more polluted the further it gets from the source, there came a time when God decreed there no longer be marriage between close relatives because of the danger of inbreeding.
ii. Even Abraham married his half-sister Sarah (Genesis 20:12). God did not prohibit such marriages until the time of Moses (Leviticus 18:9). Marrying a brother or sister was not forbidden until God forbade it.
On a metaphysical notion,
Metaphysical Bible Dictionary
Cain in Hebrew stands for - possession; acquisition. centralization, to its own center; selfishness; sharp, cutting. a lance. Cain represents the genius of evil,
When does God disallow marrying close relatives?
Well Noah and his family of eight had six laws to follow,
Gen 9:1, 'be fruitful and fill the land"
http://en.wikipedia.org/wiki/Seven_Laws_of_Noah
Prohibition of Idolatry
Prohibition of Murder
Prohibition of Theft
Prohibition of Sexual immorality
Prohibition of Blasphemy
Prohibition of eating flesh taken from an animal while it is still alive
Establishment of courts of law
then after the Exodus:
Deu 27:22 "'Cursed be he who lies with his sister, whether the daughter of his father or the daughter of his mother.' And all the people shall say, 'Amen.'
According to the Chumash, the twelve subjects of the blessings and curses are acts of the sort that transgressors could do secretly. Thus, the nation would proclaim that it abhorred stealthily committed sins, and acknowledged God would punish those who commit them.
