"And it came to pass as mankind began to increase upon the face of the Earth, and daughters were unto them; and the sons of God saw that the daughters of men were fair, and they took each of them wives of which they chose". "And there were giants on the Earth in those days and also after that when the sons of God came in unto the daughters of men. The same became mighty men which were of old and men of renown". Genesis 4:6-7