What were the Nephilim?

Question

Inspired by this question on Biblical Hermeneutics.

What were the Nephilim mentioned in Bereishis and in Bamidbar?

Bereishis 6:1-4

The Nephilim were in the earth in those days, and also after that, when the sons of God came in unto the daughters of men, and they bore children to them; the same were the mighty men that were of old, the men of renown.

Bamidbar 13:33

And there we saw the Nephilim, the sons of Anak, who come of the Nephilim; and we were in our own sight as grasshoppers, and so we were in their sight.'

Which commentaries speak about it?

Answer 1

Genesis 6:4

ד) הַנְּפִלִים הָיוּ בָאָרֶץ בַּיָּמִים הָהֵם וְגַם אַחֲרֵי כֵן אֲשֶׁר יָבֹאוּ בְּנֵי הָאֱלֹהִים אֶל בְּנוֹת הָאָדָם וְיָלְדוּ לָהֶם הֵמָּה הַגִּבֹּרִים אֲשֶׁר מֵעוֹלָם אַנְשֵׁי הַשֵּׁם:

Rashi, Ibn Ezra, Radak, Ramban (quoting Rashi and Radak), Chizkuni, and Malbim (on Genesis 8:21) all say that they were giants (ענקים). This interpretation is probably based on the only other place where the Nephilim are mentioned, Numbers 13:33, which states

וְשָׁם רָאִינוּ אֶת הַנְּפִילִים בְּנֵי עֲנָק מִן הַנְּפִלִים וַנְּהִי בְעֵינֵינוּ כַּחֲגָבִים וְכֵן הָיִינוּ בְּעֵינֵיהֶם:

Why were they called that? Ibn Ezra and Radak explain that

"ופירוש נפילים שיפול לב הרואה אותם, שיתמה מגובה קומתם."

Ramban and Abarbanel explain that they were the children of the בני האלוהים and בנות האדם.

Ibn Ezra (in his alternate commentary) explains that they were the "opposite of the גבורים" mentioned in that verse. (I'm not sure what that means.)

The פנים יפות (R. Pinchas son of R. Zvi Hirsh haLevi Horowitz, 1700's) says that they were "fallen angels." The תורה תמימה (R. Baruch Epstein, 1900's) says similarly, that they are "those that fell from heaven to earth."

(Please note that "fallen angels," while making first appearance in the Book of Enoch, an ancient Jewish book written in the 1st century BCE, were greatly popularized in Milton's Paradise Lost, published in 1667. As such, it's plausible that these last two commentaries were influenced by Paradise Lost.)

Answer 2

The Pirkei D'Rav Eliezer says these were angels that fell from heaven and married the daughters of Kayin who were dressed inappropriately, and had children that were giants.

http://hebrewbooks.org/pdfpager.aspx?req=21858&st=&pgnum=131

http://hebrewbooks.org/pdfpager.aspx?req=21858&st=&pgnum=132

Answer 3

Rav Yehudah Fatayah in his Minchat Yehudah to Genesis 6:4 suggests that they were a larger strain of humans. One should really read it inside (including his comments to previous pesukim) to understand his whole theory, but in essence he thinks that Adam was very large and Eve was small and pre-Flood humans had a great genetic diversity (my word, not his) in terms of size. But because Noah and his family were more "normal" sized humans today have less such diversity. He explains the verse in Numbers as saying some of those same "old stock" humans of Nephilim size were still around.