The question of why God allowed marriage between close relatives in Genesis, and then forbade it later on, has been a stickler for a lot of people. Cain's wife was obviously his sister or niece. Abraham married his half sister, and there were other close related marriages. But about 400 years later God forbade such marriages during the time of Moses (Leviticus 18). Today, brothers and sisters are by law not permitted to marry and have children. Why? The answer to that question is actually quite simple. Ken Ham in his book The New Answers Book explains it quite well:
" The more closely related two people are, the more likely it is that they will have similar mistakes in their genes, inherited from the same parents. Therefore, brother and sister are likely to have similar mistakes in their generic material. If there were to be a union between the two that produces offspring, children would inherit one set of genes from each of their parents. Because the genes probably have similar mistakes, the mistakes pair together and result in deformities in the children.
Conversely, the further away the parents are in relationship to each other, the more likely it is that they will have different mistakes in their genes. Children, inheriting one set of genes from each parent, are likely to end up with some of the pairs of genes containing only one bad gene in each pair. The good ones tend to override the bad so that a deformity (a serious one, anyway) does not occur. Instead of having totally deformed ears, for instance, a person may have only crooked ones. (Overall, though, the human race is slowly degenerating as mistakes accumulate generation after generation.)
However, this fact of present day life did not apply to Adam and Eve. When the first two people were created, they were perfect. Everything God made was "very good" (Genesis 1:31). That means their genes were perfect - no mistakes. But when sin entered the world because of Adam (Genesis 3:6), God cursed the world so that the perfect creation then began to degenerate, that is, suffer death and decay (Romans 8:22). Over a long period of time, this degeneration would have resulted in all sorts of mistakes occurring in the generic material of living things.
But Cain was in the first generation of children ever born. He, as well as his brothers and sisters, would have received virtually no imperfect genes from Adam and Eve, since the effects of sin and the curse would have been minimal to start with. In that situation, brother and sister could have married (provided it was one man for one woman, which is what marriage is all about, Matthew 19:4-6) without any potential to produce deformed offspring.
By the time of Moses (about 2500 years later), degenerative mistakes would have accumulated to such an extent in the human race that it would have been necessary for God to bring in the laws forbidding brother-sister (and close relative) marriage (Leviticus 18-20).
In all, there appear to be three interrelated reasons for the introduction of laws forbidding close inter-marriage.
1. As we have already discussed, there was the need to protect against the increasing potential to produce deformed offspring.
2. God's laws were instrumental in keeping the Jewish nation strong, healthy, and within the purposes of God.
3. These laws were a means of protecting the individual, and society at large. The psychological damage caused by incestuous relationships should not be minimized.
Some have claimed this means God changed His mind by changing the laws. But God didn't change His mind - because of the changes that sin brought and because God never changes. He introduced new laws for our sake. "
By George Konig
6/10/2007
www.georgekonig.org
See a list of all of our commentaries