One of the perplexing puzzles of Scripture is who were the Nephilim? The word is only used three times in Scripture, once in Genesis 6:4, and the other two times in Numbers 13:33. Genesis says only this: "When man began to multiply on the face of the land and daughters were born to them, the sons of God saw that the daughters of man were attractive. And they took as their wives any they chose. Then the Lord said, 'My Spirit shall not abide in man forever, for he is flesh: hid days shall be 120 years'. The Nephilim were on the earth in those days, and also afterward, when the sons of God came into the daughters of man and they bore children to them. These were the mighty men who were of old, the men of renown." (Gen 6:1-4 ESV) And in Numbers we read, "And there we saw the Nephilim (the sons of Anak, who come from the Nephilim), and we seemed to ourselves like grasshoppers, and so we seemed to them." (Numbers 13:33 ESV)
Early Greek manuscripts translated the Hebrew "Nephilim" as "gigantes" or "giants" based on the reading found in Numbers, and bolstered by the description of the Anakim as found in Deuteronomy (the word "Anakim" is used nine more times there). However, the problem is that Genesis does not say that the Nephilim were giants, neither does Numbers. Numbers says that Anak was a descendant of the Nephilim, and that he was a giant, and that his children were giants. This does not necessarily mean that all Nephilim were giant themselves.
What Genesis does specifically say is that the Nephilim were mighty men of old, they were men of great renown. Also it notes that the Nephilim existed in a time corresponding to the "sons of God" coming to the "daughters of man." Genesis does not explicitly say that the Nephilim were the results of these unions, but rather that the Nephilim existed in the days when this was happening. A common understanding of the passage is that the Nephilim were the result of this union, but the passage itself does not explicitly say as much, though perhaps the text intends that to be the point. In either case we cannot authoritatively say that the Nephilim were all giants, but rather that the sons of Anak were giants, and Anak was from the Nephilim.
There are a myriad of issues in the text that need to be taken apart for us to figure out what is going on and offer any possible solution to who the Nephilim are. But, no matter what answer we come up with one thing must be understood as certain: we will only be able to give an educated opinion. Our opinion may be based on strong evidence, but ultimately this ought not be a point to divide over. Paul himself says that arguing over endless genealogies is pointless and improper. Therefore, while I intend to offer my understanding and interpretation of who the Nephilim are I also want to make clear that this is just my opinion, I am not saying that Scripture is adamant on this or that anyone should make a doctrinal issue out of the Nephilim, there simply is no biblical warrant for doing such.
A very common interpretation of the passage is perhaps the most straightforward: the Nephilim are the offspring of human-angel relationships where angels took human wives and produced these children with them. Obviously in this case the angels might be better recognized as demons as the bible indicates that angels were not supposed to wed. We see in Matthew 22:30 that Jesus makes clear that angels in heaven do not wed. Therefore, if angels were taking human wives they would necessarily be abandoning their proper role in heaven.
Perhaps the main reason for thinking that the Nephilim are descendants of angels is because of the use of the term "sons of God." This term is used twice in Job to indicate angels. In Job 1:6 and 2:1 we see the term "sons of God" used directly in connection with angels. Clearly, for the writer of Job, the term had a divine significance. Thus, based on the clear indication of what is meant in Job, it becomes reasonable to read that understanding of the term back into Genesis 6.
Genesis 6:4 then becomes an explanatory verse for what we see in Jude. In Jude we read of angels who were bound in chains because they left their proper dwelling. Because the comments immediately following this section discusses Sodom and Gomorrah there is perhaps additional evidence of sexual immorality being implied against these angels. If that is the case then perhaps what Jude is referring to are the angels who sired the Nephilim, who left heaven and took wives and brought forth children, all against the will of God. Thus now these angels are awaiting punishment and humanity had to deal with the wickedness of their offspring.
While this understanding sums everything up very nicely, it also has a few major theological problems. The first problem that must be addressed has to do with who and what angels are. One thing is certain in Scripture: angels are not physical beings. Yes, angels kill and destroy, yes they can be touched and can touch things, but they are not physical. Angels are spirits according to Hebrews 1:14. This is further reinforced by the fact that angels come into the presence of God, who is himself spirit. Thus the idea of a spiritual being engaging in a physical relationship so as to bear a child seems contrary to what we find in Scripture. (Yes, Christ was begotten by the Spirit as a special miracle of God, but unless we intend to become heretics we must remember that Mary was still a virgin, thus there was no physical relationship between God and Mary.) There is no indication that God gave angels the ability to get women pregnant, unless we assume it in Genesis 6.
Angels are not physical beings living on some other planet or coming from some other place within the universe. Angels are spiritual beings whose proper dwelling is heaven. Thus in Jude what we see is Angels who abandoned their position before God and rebelled with Satan. Even Revelation discusses the idea of 1/3 of the stars of heaven (which seem to be representative of the angels) being cast out of heaven, and Satan being cast out as well. Angels are not physical, they do not have physical bodies, which is made clear by the fact of demons seeking to possess others, because they have no bodies of their own.
The second problem with the idea of the Nephilim being the offspring of angels is what is found repeated of all living things in Genesis 1. Living things were made to reproduce after their own kind. Now, exactly what "kind" means is somewhat vague, but it seems that there is a limitation to the variety that a thing can reproduce as. So dogs produce dogs, cats produce cats, and fishes produce fishes. But we see in nature there is some cross over, so that certain types of birds, fish, and other animals are capable of reproducing with what would normally be considered another species, but the possible variations are sill very limited. Frogs do not reproduce with fishes or cats.
The reason this presents a problem for the Nephilim being children of angelic and human unions is because angels and humans are two different kinds. In fact humans are a unique kind, there is nothing else like us. Humans alone were said to be made in the divine image. Thus for humans and angels to even be able to have children we would have to assume something that would radically change the whole of our understanding of Scripture and divine image: that humans and angels are the same kind of creature, in a biblical sense. As man is described as unique by Scripture, and as there is on indication of angels being the same type as man (as Psalms says, man was created a little lower than the angels) it seems this presents a major problem for those who would say humans and angels were capable of having children.
Okay, but if the Nephilim were not the result of angelic and human relationships, who were they? Here I think we can find a fairly simple answer that uses the information present in Genesis, Numbers, and Deuteronomy, and makes sense of biblical theology as well. Let us begin with the question of who the sons of God are.
I noted that "sons of God" is used in Job to refer to angels. However, there is one other place the term, "Sons of God" is used in the Old Testament. In Deuteronomy 32:8 we read, "When the Most High gave to the nations their inheritance, when he divided mankind,/ he fixed the borders of the peoples according to the number of the sons of God." (Deuteronomy 32:8 ESV) This verse doesn't seem to be of much help, until you consider the context of the passage. Once we look at the context of the passage, the meaning of "sons of God" becomes clear.
In order to understand the context of this passage you need to know how Hebrew poetry works. Hebrew poetry usually works through a repeated idea or through a central thought being brought out in different ways. So in Genesis we read, "These are the generations of the heavens and the earth when they were created, in the day that the LORD God made the earth and the heavens." See how the idea of God as creator is repeated, along with the use of the terms "earth" and "heavens." Notice that to create balance the author even reverses the order of "heavens and earth" to "earth and heavens." At the center of the whole passage, balanced between heavens and earth and created and mind, we find " the LORD God." The point of the poem is to emphasize the divine power of God as creator, to bring him glory as the one who made all things.
So, in Deuteronomy 32 we read, "They have dealt corruptly with him; they are no longer his children because they are blemished; they are a twisted and crooked generation./ Do you thus repay the LORD, you foolish and senseless people?/ Is he not your father, who created you, who made you and established you?/ Remember the days of old; consider the years of many generations;/ ask your father and he will show you, ask your elders and they will tell you./ When the Most High gave to the nations their inheritance, when he divided mankind,/ he fixed the borders of the peoples according to the number of the sons of God." (Deuteronomy 32:5-8 ESV)
The term "sons of God" in Deuteronomy 8 matches the idea of 32:5, that God has rejected these people because of their sins. They have become corrupt and wicked, and thus, though they were the children of God, now they are aliens to him. Though he was their father they rejected him and forgot him, and now they have no claim with him. Sons of God in Deuteronomy 8 shows the idea of the people of the earth in an early stage, those who God would use to develop as nations.
This use of the term should be the one given the most weight because the authorship of Genesis is the same as that of Deuteronomy. That is, it is generally accepted as tradition that Moses wrote the first five books of the bible (obviously with a later editor). If this is the case then we should use this instance of the "sons of God" as the guiding usage as it would be the closest correspondent use of the term in Scripture to what we find in Genesis. Further, since we have additional information on the Anakim in Deuteronomy, thus showing a development of what is found in Numbers, we see how the books are tied together in concept, thus, in my opinion, giving more weight to using Deuteronomy as the best source for understanding the vague identity of the Nephilim.
Using Deuteronomy helps to explain why the term Nephilim is used as well. The term itself most closely means "fallen ones". In context it does not seem that the term Nephilim is used of a specific people, that is a group descended from just one man. Often we see groups identified either from their ancestor, such as the Anakim (sons of Anak) or based on their location, such as the Caphtorim (who come from Caphtor). In the case of the Nephilim, assuming my understanding is correct, we see a people described by their condition. The Nephilim would be the fallen "sons of God" who were the powerful men used to build civilizations and who groups were named after.
Thus Anak would have come from the Nephilim and had a people named after him. But he was fallen, no longer walking in the way of God, but twisted and concerned with his own glory. He was a giant of men and used his power and strength to establish himself. In this he was a man of great renown, a man of power on the earth. But he was also a man who rejected God and repaid God with evil.
This use of Nephilim further makes sense when you consider where it first occurred in Scripture. Remember, when the bible was first written there were no chapter and header divisions. Thus the earliest manuscripts would have gone straight from chapter 5 to chapter 6. Chapter 5 of Genesis is the record of the genealogy of Adam. Adam is made by God, he fathers Seth, Seth fathers Enosh, who fathers Kenan, and all the way down to Noah, who fathers Shem, Ham, and Japheth. Then immediately we read about the "sons of God" going after the "daughters of man" and we read about the flood coming and the Nephilim being on earth. It would make sense for the Nephilim to refer to fallen men who came out of the Adamic line who abandoned the knowledge of God and instead pursued their own names. They thus bring forth the Nephilim who will establish nations (based on the fact that they are the ones who will establish names for themselves) but their fallen nature is shown in their rejection of God.
The idea of the Nephilim in Genesis 6 also shows how the repeated idea of creation and fall has become part of the cycle of life. Adam was created, he sinned and fell and caused the whole earth to become cursed. Now his children, instead of pursuing godliness and seeking to reform the earth, continue in the fallen nature of the world around them. Where there was perhaps some hope that godliness could reign through the establishing of godly offspring slowly taking over the whole earth, instead, as men multiplied, they saw what they desired and took it for themselves, just as their father did. (Notice the use of the words in Genesis 6: "saw" "attactive" "took" "chose". These words echo what we see in Genesis 3 of Eve seeing the fruit to be attractive and then taking it because she wanted it.) So the pattern of sin in the world is re-emphasized with there being only one recourse to God: he will wipe the world clean and start anew with Noah.
So, the Nephilim were not angelic or demonic children. The Nephilim is a group designation given to the fallen men who would go on to be the founders of various nations. These were men who abandoned the worship of God for the worship of themselves, and thus epitomized the fallen reality of the world. They were powerful, they were renowned, and whole civilizations would be named after them, but in the end they were merely men. And God would eventually wipe the stain of these men off of the earth through a weak people, descended from an old man and a childless woman. And God would eventually remove the stains of these people through the foolishness of the cross and the weakness of preaching; and those who were fallen would be lifted by the gentle hands of the Son of God, so they one day they might be called the sons of God, all to the glory of the Father.