Genesis 6:4
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.
Deuteronomy 2:11
9 Then the Lord said to me, “Do not harass Moab and provoke them to war, for I will not give you any of their land as your territory. This is because I have given Ar to the descendants of Lot as their possession. 10 (The Emites used to live there, a people as powerful, numerous, and tall as the Anakites. 11 These people, as well as the Anakites, are also considered Rephaites; the Moabites call them Emites. 12 Previously the Horites lived in Seir, but the descendants of Esau dispossessed and destroyed them and settled in their place, just as Israel did to the land it came to possess, the land the Lord gave them.) 13 Now, get up and cross the Wadi Zered.” So we did so.
Notes and References
"... The specific correlation between the Nephilim in Numbers 13:33 and “the sons of Anak” (verses 22, 28) would have widened the horizon for ancient readers to have inferred links between groups of various names within the biblical tradition, whether in the Masoretic text or the LXX tradition. For example, in Deuteronomy 2:10–11 an apparent gloss refers to inhabitants of Ar called “the Emim … a great and numerous and tall people” who “like the Anakim are thought to be the Rephaim” (see also verses 20–21). The correspondence chain of Giborim = Nephilim = Anakim = Rephaim, which could be inferred from reading synthetically the Hebrew of Genesis 6, Numbers 13, and Deuteronomy 2, is consistent with a translation strategy in the Greek tradition that often applied, as we have seen above, the term γίγας ('giants'), for these words. By implication, Og king of Bashan could have been related to this circle, as may be suggested by the gloss at Deuteronomy 3:11 (see also 3:13) about the unusually large size of his bed and the claim that he “alone was left remaining from the remnant of the Rephaim (מיתררפאים)” ..."
Stuckenbruck, Loren T. The Myth of Rebellious Angels: Studies in Second Temple Judaism and New Testament Texts (p. 6) Mohr Siebeck, 2014