Hebrew Bible

Genesis 6:4

1 When humankind began to multiply on the face of the earth, and daughters were born to them, 2 the sons of God saw that the daughters of humankind were beautiful. Thus they took wives for themselves from any they chose. 3 So the Lord said, “My Spirit will not remain in humankind indefinitely, since they are mortal. They will remain for 120 more years.” 4 The Nephilim were on the earth in those days (and also after this) when the sons of God would sleep with the daughters of humankind, who gave birth to their children. They were the mighty heroes of old, the famous men. 5 But the Lord saw that the wickedness of humankind had become great on the earth. Every inclination of the thoughts of their minds was only evil all the time. 6 The Lord regretted that he had made humankind on the earth, and he was highly offended.

Date: 5th Century B.C.E. (Final composition)
* Dates are based on scholarly estimates
Hebrew Bible

Numbers 13:33

31 But the men who had gone up with him said, “We are not able to go up against these people, because they are stronger than we are!” 32 Then they presented the Israelites with a discouraging report of the land they had investigated, saying, “The land that we passed through to investigate is a land that devours its inhabitants. All the people we saw there are of great stature. 33 We even saw the Nephilim there (the descendants of Anak came from the Nephilim), and we seemed like grasshoppers both to ourselves and to them.”

Date: 5th Century B.C.E. (Final composition)
* Dates are based on scholarly estimates