Are the Nephilim the same as the 'mighty men' in Genesis 6:4?

Not exactly — the Hebrew text of Genesis 6:4 keeps them formally distinct, even though readers have long merged them.

Here's the full verse:

"The Nephilim were on the earth in those days, and also afterward, when the sons of God came in to the daughters of man and they bore children to them. These were the mighty men who were of old, the men of renown." — Genesis 6:4

Read closely, the verse describes two things: the Nephilim (הַנְּפִלִים, H5303) who "were on the earth," and separately, "the mighty men" (הַגִּבֹּרִים, H1368) who are named as the offspring of the union between "the sons of God" (בְּנֵי הָאֱלֹהִים, H1121 + H0430) and human women. Grammatically, the antecedent of "these" (hemmah) pointing back to the mighty men is contested precisely because the verse keeps the Nephilim and the offspring in separate clauses. Treating "Nephilim" and "the offspring of the sons of God" as one and the same group is a reading of the verse — a very old and defensible one — not something the Hebrew states in so many words.

That equation, though, has ancient pedigree of its own. The Septuagint — the Greek translation of the Hebrew Bible made in the third century BC — collapses the distinction by using one Greek word, γίγαντες (gigantes, "giants"), for both הַנְּפִלִים and הַגִּבֹּרִים in the same verse:

"And the gigantes were on the earth in those days... those were the gigantes of old, the men of renown." — LXX Genesis 6:4

So the merge that later Jewish and Christian tradition ran with — Nephilim = giant offspring of angels and human women — isn't a modern invention. The oldest Greek witness to the text made that identification independently, roughly the same era as the earliest parts of 1 Enoch were taking shape. Which text influenced which can't be settled, and nothing about the argument needs it settled.

What stays true on both sides: the Hebrew keeps the two words apart, and Genesis itself never states that the Nephilim are the divine-human offspring — that step is an interpretation, even a very early one, not a datum the text hands you outright. The word "Nephilim" itself is rare — it appears in only one other verse in the whole Hebrew Bible, Numbers 13:33, where the spies use it for the ordinary human "sons of Anak," with no hint of angels or heavenly beings anywhere in the line.

The full study traces this distinction through the Hebrew grammar, the Septuagint's translation choice, and what it does and doesn't cost a well-known scholarly argument that leans on the Nephilim-as-offspring reading. Read the full study: Annus on the Origin of Watchers — Testing the Hebrew Half