As we go on with the story of the Nephilim, getting a grasp on what angels actually are is essential, so let us look at a few of the biblical descriptions of angels to gain an understanding of what they are and what they are not:
- Hebrews 1:14 tells us angels are "ministering spirits" (pneumata)-- creatures of breath, spirit-beings rather than flesh, that do what God tells them to benefit those about to inherit salvation (Christians);
- Luke 24:39 tells us spirits have not flesh and bone, they’re not corporeal, even if they take the form of man;
- Luke 20:35-36 tells us the resurrected are equivalent to angels in that they do not die-- so angels do not die;
- Luke 20:35-36 also tells us the resurrected are equivalent to angels in that they neither marry nor are given in marriage-- so angels do not reproduce sexually.
The Bible doesn't give us all that much information about angels, not near as much as humans have an appetite for anyhow. Problems arise when we try to fill the knowledge gap by turning to uninspired works of the ancient past, even if those sources are presumably Jewish. Even if those sources are cited or alluded to in the inspired scriptures we do have. Even if those sources were found among copies of writings which are inspired. One who takes sola scriptura as the rule of faith and conduct doesn't give credence to myths and endless genealogies, which can only promote unhelpful speculations.
We are told in Job 1:6 and 2:1 that Satan reported to God amidst the angels presenting themselves to God. Satan is referred to under the term "also,” (Hebrew: gam), which, it seems to me, is meant to distinguish him in some way from all the sons of God. Even though he was the same type of being (a presumption in Job rather than being explicitly stated), his distinction from the sons of God is pointed out unmistakably. He's definitely not treated as the same, as if he's just another angel.
Which bring us to the lack of distinction in Genesis 6 that would be necessary if "sons of God" were fallen angels in that account. Presumably from Revelation 12, fallen angels, like Satan himself, fell in Genesis 3. Satan was cursed there, which is certainly not what happens to an unfallen angel. The curse kind of makes it impossible to not see Satan from that point on in a light that would preclude him from the company of the sons of God. It would make him an "other" from that point on.
To have disobedient angels mating with humans after Satan had been cursed would have required those fallen angels to be distinguished from sons of God in some way as well. Perhaps they would have been called "demons" or "unclean," or by some other distinction, but they definitely would not have been called "sons of God." If this circumstance is envisioned as the instance of their falling, that too is fraught with problems, because taking wives (plural) and having children doesn't happen in a moment. It takes time. At what point would it have been sinful, stopped by God and judged by imprisonment?
The only thing judged in Genesis 6 is flesh (human and animal) for violence by death.
In a nutshell, then, angels are incorporeal beings incapable of breeding among themselves, let alone humans. They do not die. Fallen angels are no longer called "sons of God" but evil or unclean spirits, demons, devils and Satan and his angels. The notion of them producing hybrid offspring which God had to judge by the flood is, well, ridiculous.
