Genesis 6:4-6

The Nephilim were on the earth both in those days and afterward, when the sons of God came to the daughters of mankind, who bore children to them. They were the powerful men of old, the famous men. When the LORD saw that man’s wickedness was widespread on the earth and that every scheme his mind thought of was nothing but evil all the time, the LORD regretted that He had made man on the earth, and He was grieved in His heart.