What does “sons of God” (Gen 6:2) mean?

There are three theories, about what the “sons of God” are, that I want to consider: (1) they are angels, presumably fallen angels; (2) they are the faithful from the line of Seth, those who called on the name of the Lord or walked with the Lord; or (3) they are all men. Now, there is little evidence internal to the Bible that the phrase here meant demons or demonic spirits (fallen angels), whether embodied themselves or inhabiting the bodies of wicked men—though the phrase “sons of God” does sometimes mean angels. The famous but certainly pseudepigraphal (i.e., falsely attributed) Book of Enoch suggests it; but it was written in the 100s AD, not at all by Enoch, and represents a highly conjectural theory, not scripture. Observe, in support of the line of Seth theory, that the previous two chapters did explain and contrasted in detail the two different lines—and that these lines come at the end of the toledoth about the line of Seth. This then raises the question: did the lines intermarry? And if so, what was the result? We are told what the result was, and so we should perhaps settle the question in the context of the remarks about nephilim in Gen 6:4. As to the third theory, this is also intiguing, because, as Sailhamer has argued, the “sons of God” might well be all men, because Adam was created by God. In that case, the “daughters of men” would be women because Eve was made of Adam’s rib. Then the comments in Gen 6:1-2 regard the totality of the “multiplying” generations of man, of all men, who are shortly to be done away with for their wickedness.

What does “My spirit shall not always strive with man” (Gen 6:3) mean, and what does this have to do with limiting his years to 120?

This is another hard saying that is not made particularly clearer or more certain in other translations. The root of the Hebrew word that “strive” translates, דִּין or din, can mean variously judge, vindicate, or abide (at least).The context is essential to fixing the sense. So note that it is because man is flesh that the Lord’s spirit will not “strive” with man, and that, therefore, his days will be limited to 120 years. Moreover, what has changed is that man has become wicked, and so God is grieved (Gen 6:5-6). This seems fairly plainly to suggest that, because man is wicked, he should not live so long and his years should be cut short. Note the author is being very explicit here in passing about something readers often observe to themselves, namely, that the lifespans of the postdiluvian patriarchs became gradually shorter; while Noah, who was born and lived most of his days before the Flood, lived to be 950, Shem lived to 600, Abraham to 180, and Moses to 120. So a broad gloss of the thought being conveyed is something like this: “My spirit, the spirit of God which I blew into Adam and which gives man life, will not always abide with and govern man—and thus he is mortal—and thus also he will not merely die, as all but Enoch have done, but he will live only 120 years because of his wickedness which is indeed “from his youth” (Gen 8:21).

Who or what were the “giants in the earth in those days” (Gen 6:4)?

This is one of the most puzzling texts in the Bible. The KJV translation “giants” is from Septuagint translation, γίγαντες or gigantes, of the Hebrew word נְפִיל, nephilim. This word can also mean “the fallen [ones],” suggesting corrupt, wicked men, the word itself most likely from נָפַל, naphal, “to fall.” This is a very slender bit of linguistic evidence on which to build notions of demon-spawned giants, which is a common theory. The reason I personally find this theory unlikely is simply that there is no other evidence in the Bible suggesting either that demons can sire earthly offspring or that there were supernaturally large giants, and rarely if ever is there so slender evidence offered for such theologically consequential creatures. If the author wanted you to believe in demon-spawned giants, surely he would have said more. Besides, there are much more reasonable theories, associated with interpretations (2) and (3), above, of the “sons of God.” Here then is the summary case for another theory. Note first that Gen 6:1-8 comes at the end of two genealogies—not separated in the original by chapters—describing the corruption of Cain’s line and the comparative righteousness of Seth’s. These verses serve as a grim conclusion to two toledoth sections about men who, whether regardless how their family line began, mostly became wicked and all-too-mortal. Then we are told, by way of summarizing the outcome of it all, that men were fruitful and multiplied, and “the sons of Gods saw the daughters of men,” etc. These (so to speak) pregnant remarks, I propose, crucially advance the narrative by explaining how Seth’s line of Lord-callers and walkers-with-God were corrupted: basically, Seth’s line, dignified in the description as “sons of God,” did not abstain from marrying the beautiful but wicked women of Cain’s line. The implication of the verses is similar to the many instances of Israelites intermarrying with “strange women” and being corrupted thereby. Indeed, the offspring of such unions were “mighty men which were of old, men of renown” (6:4), but immediately we are told, “God saw that the wickedness of man was great in the earth” (6:5). One thinks of Gilgamesh and other kings who claimed divine blood (the epic says he was two-thirds god and one-third man); the wording in the text is winking at such myths, particularly considering that 6:4’s “and also after that,” i.e., after the Flood there would be similarly arrogant strongmen, supposedly demigods but really just corrupt and powerful men. Indeed, the text may suggest that all men were like the nephilim insofar as the more divine and righteous cultural features all but died due to intermarriage. So the cultural dominance of Cain’s line was total, and Noah’s family was therefore the last remnant of the Seth line.

In describing the the corruption of man, why focus on “every imagination of the thoughts of his heart” (Gen 6:5)? Why not focus on evil actions?

The word translated “imagination” is rendered “intent” by the NASB and “inclination” by the NIV; the Hebrew יֵצֶר, yetser, is glossed “a form, framing, purpose.” In any case, we are speaking of the intentions out of which actions begin. God could see into men’s thoughts, and they matter greatly in the OT and NT alike. One of the deep and easy-to-miss themes of the Bible is the crucial importance of having the right beliefs and attitudes; foolish and vicious thoughts are often said to result in evil acts, and even the Ten Commandments has a law governing emotions and motives (the tenth, concerning envy). Considering all this, the reason for the focus on the “imagination of the thoughts of his heart” must be theological: motives and imaginations and thoughts are every bit as significant as acts, for a spiritual creator. Ultimately, the true corruption of mankind was the corruption of his heart.