I will include Appendices 23 & 25 from the Companion Bible by E W Bullinger. The Companion Bible is a King James Version Bible with side companion notes and 198 Appendices by Bullinger. In my opinion, Bullinger was the finest theologian of the 19th century and he was the only Christian scholar that Dr. C D Ginsburg allowed to proofread his work, 'The Massorah', as Ginsburg considered him to be the smartest and most well thought out theologian of his time.
Appendix 23: The Sons of God in Genesis 6:2,4.
http://www.therain.org/appendixes/app23.html
Appendix 25: The Nephilim or Giants of Genesis 6.
http://www.therain.org/appendixes/app25.html
It is only by the Divine specific act of creation that any created being can be called "a son of God". For that which is "born of the flesh is flesh". God is spirit, and that which is "born of the Spirit is spirit" (John 3:6). Hence Adam is called a "son of God" in Luke 3:38. Those "in Christ" having "the new nature" which is by the direct creation of God (2Corinthians 5:17. Ephesians 2:10) can be, and are called "sons of God" (John 1:13. Romans 8:14, 15. 1John 3:1).
This is why angels are called "sons of God". In every other place where the expression is used in the Old Testament. Job 1:6; 2:1; 38:7. Psalms 29:1; 89:6. Daniel 3:25. We have no authority or right to take the expression in Genesis 6:2, 4 in any other sense. Moreover, in Genesis 6:2 the Septuagint renders it "angels".
Angels are called "spirits" (Psalm 104:4. Hebrews 1:7, 14), for spirits are created by God.
That there was a fall of the angels is certain from Jude 6.
The nature of their fall is clearly stated in the same verse. They left their own habitation Strong's Greek 3613 (oiketerion). This word occurs only in 2 Corinthians 5:2. In Jude 6, it is used of the spiritual (or resurrection) body.
The nature of their sin is stated to be "in like manner" to that of the subsequent sins of Sodom and Gomorrah, Jude 7.
The time of their fall is given as having taken place "in the days of Noah" (1 Peter 3:20. 2 Peter 2:7), though there may have been a prior fall which caused the end of "the world that then was" (Genesis 1:1, 2. 2 Peter 3:6).
For this sin they are "reserved unto judgement", 2 Peter 2:4, and are "in prison", 1 Peter 3:19.
Their progeny, called Nephilim (translated "giants"), were monsters of iniquity; and, being superhuman in size and character, had to be destroyed (see Appendix 25). This was the one and only object of the Flood.
Only Noah and his family had preserved their pedigree pure from Adam (Genesis 6:9). All the rest had become "corrupt". The only remedy was to destroy it. (It is the same word in verse 17 as in verses 11, 12.) See further under Appendix 25 on the Nephilim.
This irruption of fallen angels was Satan's first attempt to prevent the coming of the Seed of the woman foretold in Genesis 3:15. If this could be accomplished, God's Word would have failed, and his own doom would be averted.
As soon as it was made known that the Seed of the woman was to come through Abraham, there must have been another irruption, as recorded in Genesis 6:4, "and also after that" (that is to say, after the days of Noah, more than 500 years after the first irruption). The aim of the enemy was to occupy Canaan in advance of Abraham, and so to contest its occupation by his seed. For, when Abraham entered Canaan, we read (Genesis 12:6) "the Canaanite was then (that is to say, already) in the land."
The progeny of the fallen angels with the daughters of Adam (see notes on Genesis 6, and Appendix 23, are called in Genesis 6, Ne-phil´-im, which means fallen ones (from naphal, to fall). What these beings were can be gathered only from Scripture. They were evidently great in size, as well as great in wickedness. They were superhuman, abnormal beings; and their destruction was necessary for the preservation of the human race, and for the faithfulness of God's Word (Genesis 3:15).
This was why the Flood was brought "upon the world of the ungodly" (2Peter 2:5) as prophesied by Enoch (Jude 14).
But we read of the Nephilim again in Numbers 13:33: "there we saw the Nephilim, the sons of Anak, which come of the Nephilim". How, it may be asked, could this be, if they were all destroyed in the Flood? The answer is contained in Genesis 6:4, where we read: "There were Nephilim in the earth in those days (that is to say, in the days of Noah); and also AFTER THAT, when the sons of God came in unto the daughters of men, and they bare children to them, the same became [the] mighty men (Hebrew gibbor, the heroes) which were of old, men of renown" (literally, men of the name, that is to say, who got a name and were renowned for their ungodliness).
So the phrase "after that", that is to say, after the Flood, there was a second irruption of these fallen angels, evidently smaller in number and more limited in area, for they were for the most part confined to Canaan, and were in fact known as "the nations of Canaan". It was for the destruction of these, that the sword of Israel was necessary, as the Flood had been before.
As to the date of this second irruption, it was evidently soon after it became known that the seed was to come through Abraham; for, when Abraham came out from Haran (Genesis 12:6) and entered Canaan, the significant fact is stated: "The Canaanite was then (that is to say, already) in the land." And in Genesis 14:5 they were already known as "Rephaim" and "Emim", and had established themselves at Ashteroth Karnaim and Shaveh Kiriathaim.
In chapter 15:18-21 they are enumerated and named among Canaanite Peoples: "Kenites, and the Kenizzites, and the Kadmonites, and the Hittites, and the Perizzites, and the Rephaims, and the Amorites, and the Girgashites, and the Jebusites" (Genesis 15:19-21; compare Exodus 3:8, 17; 23:23. Deuteronomy 7; 20:17. Joshua 12:8).
These were to be cut off, and driven out, and utterly destroyed (Deuteronomy 20:17. Joshua 3:10). But Israel failed in this (Joshua 13:13; 15:63; 16:10; 17:18. Judges 1:19, 20, 28, 29, 30-36; 2:1-5; 3:1-7); and we know not how many got away to other countries to escape the general destruction.
As to their other names, they were called Anakim, from one Anak which came of the Nephilim (Numbers 13:33¹), and Rephaim, from Rapha, another notable one among them.
From Deuteronomy 2:10, they were known by some as Emim, and Horim, and Zamzummim (verses 12, 20) and Avim (verse 23), etc.
As Rephaim they were well known, and are often mentioned.
By reading all these passages the Bible student may know all that can be known about these beings.
It is certain that the second irruption took place before Genesis 14, for there the Rephaim were mixed up with the five nations or peoples, which included Sodom and Gomorrha, and were defeated by the four kings under Chedorlaomer. Their principal locality was evidently "Ashtaroth Karnaim"; while the Emim were in the plain of Kiriathaim (Genesis 14:5).
Anak was a noted descendant of the Nephilim; and Rapha was another, giving their names respectively to different clans. Anak's father was Arba, the original builder of Hebron (Genesis 35:27. Joshua 15:13; 21:11); and this Palestine branch of the Anakim was not called Arbahim after him, but Anakim after Anak. They were great, mighty, and tall (Deuteronomy 2:10, 11, 21, 22, 23; 9:2), evidently inspiring the ten spies with great fear (Numbers 13:33). Og king of Bashan is described in Deuteronomy 3:11).
Moreover, we have in these mighty men, the "men of renown," the explanation of the origin of the Greek mythology. That mythology was no mere invention of the human brain, but it grew out of the traditions, and memories, and legends of the doings of that mighty race of beings; and was gradually evolved out of the "heroes" of Genesis 6:4. The fact that they were supernatural in their origin formed an easy step to their being regarded as the demi-gods of the Greeks.
Thus the Babylonian "Creation Tablets", the Egyptian "Book of the dead", the Greek mythology, and heathen Cosmogonies, which by some are set on an equality with Scripture, or by others adduced in support of it, are all the corruption and perversion of primitive truths, distorted in proportion as their origin was forgotten, and their memories faded away.
As for what I have learned over the years from my own studies, I will briefly describe.
Of the three main views associated with Genesis 6, namely:
1/ The Sethite Interpretation.
2/ The Despot Interpretation
3/ The Fallen Angel Interpretation
I believe #3 to be the most accurate.
According to this view, the ‘sons of God’ of verses 2 and 4 are angels, who instead of being born of woman as the rest of us have been, instead escaped that habitation and came to the earthly dimension in human form (See the book of Jude).They took the form of masculine human-like creatures. These angels married women of the human race (either Cainites or Sethites) and the resulting offspring were the Nephilim. The Nephilim were giants with physical superiority and therefore established themselves as men of renown for their physical prowess and military might. This race of half human creatures was wiped out by the flood.
My basic presupposition in approaching our Biblical text is that we should let the Bible define its own terms. The Bible interprets the Bible. If biblical definitions are not to be found then we must look at the language and culture of contemporary peoples. What is interesting, is that the Bible does define the term ‘the sons of God’ for us.
Now there was a day when the sons of God came to present themselves before the Lord, Satan also came among them (Job 1:6).
Again there was a day when the sons of God came to present themselves before the Lord, and Satan came among them to present himself before the Lord (Job 2:1).
When the morning stars sang together, and all the sons of God shouted for joy? (Job 38:7, Psalm 89:6; Daniel 3:25).
Scholars who reject this view readily acknowledge the fact that the precise term is clearly defined in Scripture.The reason for rejecting the fallen angel interpretation is that such a view is said to be in violation of both reason and Scripture.
The primary passage which is said to be problematical is that found in Matthew’s gospel, where our Lord said, “You are mistaken, not understanding the Scriptures, or the power of God. For in the resurrection they neither marry, nor are given in marriage, but are like angels in heaven” (Matthew 22:29-30).
We are told that here our Lord said that angels are sexless, but is this really true? Jesus compared men in heaven to angels in heaven. Neither men nor angels are said to be sexless in heaven but we are simply told that in heaven there will be no marriage. There are no female angels with whom angels can generate offspring. Angels were never told to ‘be fruitful and multiply’ as was man.
When we find angels described in the book of Genesis, it is clear that they can either assume a human-like form, or look human and that their sex is masculine. The writer to the Hebrews mentions that angels can be entertained without man’s knowing it (Hebrews 13:2). The perverted men of Sodom were very capable of judging sexuality. They were attracted by the ‘male’ angels who came to destroy the city (Genesis 19:1-5).
In the New Testament, two passages seem to refer to this incident in Genesis 6, and to support the angel view:
For if God did not spare angels when they sinned, but cast them into hell and committed them to pits of darkness, reserved for judgment; (II Peter 2:4).
And angels who did not keep their own domain, but abandoned their proper abode, He has kept in eternal bonds under darkness for the judgment of the great day (Jude 6).
These verses would indicate that some of the angels who fell with Satan were not content with their ‘proper abode’ and therefore began to live among men (and women) as men. God’s judgment upon them was to place them in bonds so that they can no longer promote Satan’s purposes on earth as do the unbound fallen angels who continue to do his bidding.
The result of the union between fallen angels and women is rather clearly implied to be the Nephilim. While word studies have produced numerous suggestions for the meaning of this term, the biblical definition of this word comes from its only other instance in Scripture, Numbers 13:33:
There also we saw the Nephilim (the sons of Anak are part of the Nephilim); and we became like grasshoppers in our own sight, and so we were in their sight.
I therefore understand the Nephilim to be a race of super-humans who are the product of this angelic invasion of the earth.
This view not only conforms to the biblical use of the expression ‘sons of God,’ it also best fits the context of the passage.
Genesis 6 describes a desperate attempt on the part of Satan to attack the godly remnant that is named in chapter 5. So long as a righteous seed is preserved, God’s promise of salvation hangs over the head of Satan, threatening of his impending doom.
I could go on but I have written enough. The flood is a non-salvation issue as I have mentioned before. I chose the fallen angel interpretation as the best explanation from the Biblical text. If others disagree, no worries. It is up to them to explain their interpretation.