It is difficult to deny God’s approval of incest if you read Genesis 19:30-36. It is undeniable that God allowed “incest” in the early centuries of humanity. At the time, however, incest did not exist; it was just marrying a close relative. Adam and Eve were the only two human beings on Earth; their descendants had no choice but to intermarry, and reproduce, with their siblings, and close relatives. The following generations had to do the same, including Noah and his descendants. It is important to mention that Genesis 2:24 seems to indicate that marriage and sexual relations between parents and children were never allowed by God.
Coming back to Lot, the Bible tells us that he, following the Lord's instructions to escape Sodom's destruction, went up out of Zoar (Bela in Genesis 14:8). Lot did not feel safe in Zoar and decided to go up the mountain, together with his wife and two daughters. During their climbing, Lot's wife, disobeying precise commandments from God, turned her sight towards the condemned city, and perished. The Scriptures tell us she became a pillar of salt. Lot kept going with his two daughters until they got to a safe dwelling in a cave.
His daughters wrongly realized that they would not have many opportunities to enter sexual relationships. It seemed to them that their father was the only man available; all the others were massacred during Sodom's annihilation. Are we to assume these two young ladies did not know about other cities in the area? Apparently not, because after discussing the situation between themselves, they agreed to get their father drunk by giving him some wine. (The Bible does not explain where they obtained the wine.) Although the oldest daughter was first to have sex with her father, their plan called for alternation until both became pregnant, which they did. The two sons born of incest, Moab and Ammon, became the progenitors of two of the greatest adversaries of Israel, the Amorites and the Moabites. Surprisingly, the oldest daughter never lied about her son’s origin. She named him Moab, which means “from father.”
However, we must distinguish amidst “marriage between close relatives” which for many centuries were permitted, and accepted, and “incestuous relationships” prohibited after God commanded against them in Leviticus 18:6-18. In other words, until God commanded against it, it was not incest. Intermarriage among close family members was a necessity in the generations immediately following Adam and Noah, and was not a sinful perversion.
I fail to understand this drama. I cannot believe Lot! He was drunk during nobody knows how many nights, had sex with both his daughters, and never knew what happened. Think about it for a moment! Assuming he had an inexhaustible supply of wine, are we to believe he was so drunk he didn't realize he was having sex with the only two women in the cave, his daughters? To some, Lot's incestuous fornication is forgiven because he was unwilling to do it; his daughters raped him. I don’t think so!
Lot's is not the only example of incest in the Bible. We read in Genesis 4 about Cain leaving for the land of Nod with his wife. Who is this wife? Some scholars believe Cain married one of his sisters. Similarly, all of his siblings married their female relatives. Adam and Eve's progeny seems to be the only answer. The Bible does not mention other people on Earth; accordingly, all inhabitants at this time descended from them. On the other hand, serious students of the Bible question the validity to this assertion and insist that Earth was well populated outside of the closed environment of paradise.
In Genesis 20:12, we read about Abraham marrying Sarah, his half-sister. She was the daughter of his father. In this case, the Lord not only accepted Abraham status but promised to give them progeny. Furthermore, in a clearly adulterous relationship, seemingly approved and even suggested by his wife, Abraham had a son, Ishmael, with one of his slaves, Hagar. Ishmael would later become the progenitor of the current Muslim religion.
I cannot fail to mention Moses’ father, Amram, who married his aunt Jochebed (Exodus 6:20), and David’s son, Amnon, having sex with his half-sister Tamar (2 Samuel 13). This relationship could be forgiven because Tamar was an unwilling participant in the act. She was raped by Amnon.
After God commanded against it until our current times, incest is strongly discouraged. Most contemporary scientists agree that reproduction between closely related individuals carries a high risk of causing genetic abnormalities. In the early days of humanity, though, this was not a risk because our genetic code was relatively free of defects. Based on the facts, the incestuous relationships described in the Bible, before the time of Moses, cannot be equaled with modern-day incest. Contemporary science has demonstrated that incest is medically unsafe. The biblical key is that sexual relations between members of the same family were viewed differently before and after Leviticus 18:6-18.