Genesis 6:1-4

The number of people on earth began to grow. Daughters were born to these people. The sons of God saw that these girls were beautiful. And they married any of them they chose. The Lord said, “My Spirit will not remain in human beings forever. This is because they are flesh. They will live only 120 years.” The Nephilim were on the earth in those days and also later. That was when the sons of God had physical relations with the daughters of men. These women gave birth to children, who became famous. They were the mighty warriors of long ago.