Who Did Cain Marry?

Q. I have studied over and over about Cain and his wife, and I have questioned where did Cain’s wife come from. What God has showed me that, there were people before Adam and eve, because, and remember Satan and his angels were thrown down from heaven, so they became flesh. Saying that Cain must have married his offspring would be saying that god allowed sin. Now I’m doing a study on Noah’s time. Please respond to my feedback, you might have a better insight. I’m always ready to learn and get close to God.

A. Someone might have taught you that, but it wasn’t God.  His word indicates that Adam was the first man and Eve the first woman.  Cain didn’t marry one of his daughters.  He married a sister or a niece. This was not a sin and was his only option.  Marrying a close relative was not forbidden until much later.  In fact Abraham married his half sister Sarah, Rebekah was Isaac’s niece, and a two of Jacob’s 4 wives were his cousins. All these unions had God’s blessing.