Genesis 6:2-4

Darby Translation

² that the sons of God saw the daughters of men that they were fair, and took themselves wives of all that they chose.

³ And Jehovah said, My Spirit shall not always plead with Man; for he indeed is flesh; but his days shall be a hundred and twenty years.

⁴ In those days were the giants on the earth, and also afterwards, when the sons of God had come in to the daughters of men, and they had borne [children] to them; these were the heroes, who of old were men of renown.