Cain was the first child of Adam and Eve recorded in Scripture. He and his brothers, Abel, Genesis 4:2, and Seth, Genesis 4:25, were part of the first generation of children ever born on this earth. Even though these three males are specifically mentioned, Adam and Eve had other children.
Here we read a statement that sums up the life of Adam and Eve. During their lives, Adam and Eve had a number of male and female children. In fact, the Jewish historian Josephus wrote, ‘The number of Adam’s children, as says the old tradition, was thirty-three sons and twenty-three daughters.’
Scripture doesn’t tell us how many children were born to Adam and Eve, but considering their long-life spans, it would seem logical to suggest there were many. Remember, they were commanded to ‘be fruitful, and multiply’, Genesis 1:28
We’re not told when Cain married or many of the details of other marriages and children, but we can say for certain that Cain’s wife was either his sister or a close relative.
A closer look at the Hebrew word for ‘wife’ in Genesis reveals something readers may miss in translation. It was more obvious to those speaking Hebrew that Cain’s wife was likely his sister, although there is a small possibility that she was his niece, but either way, a brother and sister would have married in the beginning.
The Hebrew word for ‘wife’ used in Genesis 4:17, the first mention of Cain’s wife, is ‘ishshah’, and it means, ‘woman/wife/female.’ The word ‘ishshah’ is the word for ‘woman,’ and it means ‘from man.’ The word is used back in Genesis 2:23. Thus, Cain’s wife is a descendant of Adam, man. Therefore, she had to be his sister, or possibly niece.
This seems foreign to us today but back in the beginning, when there was only the first generation, brothers would have had to marry sisters or there wouldn’t have been any more generations!
We have to remember that in Cain’s time there was no command not to marry a sister. This command came thousands of years later and Cain cannot be held responsible for a law that wasn’t in effect at his time. At the time of the giving of the Law and the Old Covenant to Israel incest is clearly denounced, Leviticus 18:6 / Leviticus 20:17 / Deuteronomy 27:22.
"Come to me, all you who are weary and burdened, and I will give you rest."