Genesis 6:4
One of the most amazing facts revealed by paleontology (the study of fossilized remains of creatures which inhabited the earth in a former age) is that nearly all modern animals were once represented by larger ancestors. One thinks of the mammoths and cave bears, giant cockroaches and dragonflies, and huge reptiles like the dinosaurs. Along with them are occasionally found giant human footprints, suggesting indeed that “there were giants in the earth in those days.” Not only in the Bible, but in numerous other ancient books, are preserved traditions of giants.
With such a uniform testimony from ancient tradition, and with paleontological evidence as well, it is a superficial sophistication which ignores the possibility that these data may contain primitive reflections of the real events and characters described historically here in the Genesis record.
The children of the unions of the demonically controlled men and women of this period are the ones said to have become the “giants,” the mighty men of old. The word in the Hebrew is nephilim and comes from the verb naphal (“fall”). Though some commentators suggest that the word means “those who fall upon”—that is, “attackers”—the more natural and probable meaning is “those who have fallen,” probably a reference to the nature of their pseudoparents, the fallen angels. The name came also to mean “giants” and was applied later to the giants seen in Canaan by the Israelite spies (Numbers 13:33). The word was so understood by the translators of Genesis into Greek, rendering the word in the Septuagint by gigantes.
As to why children born of demon-controlled parents should grow into giants, we can make at least a reasonable supposition, though, in the absence of Biblical revelation on the subject, it can be no more than that. Modern genetics has shown there are two basic causes of variations in physical characteristics among men, namely mutations and recombinations. In the genetic system is a tremendous number of factors for different characteristics, some dominant in a particular population, some latent or recessive. These can be “recombined” in various ways to allow an almost unlimited variation in physical features. Recombination, however, can operate only on factors which are already implicitly present in the genes. Mutations, on the other hand, can introduce new features which were not present at all, by responding to external influences whose energies effect random changes in the genetic system.
Factors for large physical stature apparently have resided from the beginning in the created gene pool of the human population. Their emergence as frequent or dominant characteristics in a specific population might result by chance in a small inbreeding population or else might result by design in the case of controlled manipulation of the genes by breeders understanding enough about the genetic process to do this. Geneticists today appear on the verge of breakthroughs which would permit exactly such “genetic engineering” as this sort of thing to be accomplished on a practical basis.
It is believed that mutations can also produce “giantism.” The strange process of cloning, by which geneticists think they will one day be able to produce a race of carbon copies of Einstein (or “Wilt the Stilt” Chamberlain, or whatever they want) by implantation of body cells in human fertilized eggs might be still another means of doing this.
The point is that, if modern geneticists can discuss with all seriousness the imminent possibility of accomplishing such things, then it is not unlikely that knowledge of these secrets could have been available to the angelic (and demonic) hosts. Having gained essentially complete control over both minds and bodies of these antediluvian parents, these fallen “sons of God” could then, by some such genetic manipulation, cause their progeny to become a race of monsters. The latter also then would be under their control and possession as well.
The demoniacal combination of the materialism and ungodliness of the Cainitic civilization in general, with this irruption of the Serpent’s seed directly into large numbers of the human race and then with the thrusting forth of hordes of the monstrous offspring of these unlawful unions, all led to conditions in the world which were finally intolerable even to a God of compassion and long-suffering.
The demon-possessed men and their progeny, along with all the other godless inhabitants of the antediluvian world, were soon to perish in the waters of the Flood. These waters are now the waters of the sea and it may well be these that are referred to in connection with the final judgment when it says that “the sea gave up the dead which were in it” (Revelation 20:13). The evil spirits who indwelt their bodies have been imprisoned in Tartarus (2 Peter 2:4) and are probably “the spirits in prison which once were disobedient when the longsuffering of God waited in the days of Noah” (1 Peter 3:19, 20), to whom Christ went in the Spirit after His death to proclaim His ultimate victory over their evil purposes.
There were giants “also after that,” in the days of the Canaanites, and these were likewise known as, among other things, the Nephilim (Numbers 13:33). Humanly speaking, they were descended from Anak, and so were also known as the Anakim. These people were, of course, known to Moses and it was probably he who editorially inserted the phrase “and also after that” into Noah’s original record here in Genesis 6:4. Moses probably also inserted the information that these were the “mighty men of old, men of renown,” men whose exploits of strength and violence had made them famous in song and fable in all nations in the ages following the Flood. To rebellious men of later times, they were revered as great heroes; but in God’s sight they were merely ungodly men of violence and evil.
Filled with Violence
Just as world conditions in the days before the Flood presaged a coming catastrophe, so will world conditions in the last days of this age foreshadow an even greater catastrophe. Some of these characteristics are summarized as follows:
(1)     Preoccupation with physical appetites (Luke 17:27)
(2)     Rapid advances in technology (Genesis 4:22)
(3)     Grossly materialistic attitudes and interests (Luke 17:28)
(4)     Uniformitarian philosophies (Hebrews 11:7)
(5)     Inordinate devotion to pleasure and comfort (Genesis 4:21)
(6)     No concern for God in either belief or conduct (2 Peter 2:5; Jude 15)
(7)     Disregard for the sacredness of the marriage relation (Matthew 24:38)
(8)     Rejection of the inspired Word of God (1 Peter 3:19)
(9)     Population explosion (Genesis 6:1, 11)
(10)     Widespread violence (Genesis 6:11, 13)
(11)     Corruption throughout society (Genesis 6:12)
(12)     Preoccupation with illicit sex activity (Genesis 4:19; 6:2)
(13)     Widespread words and thoughts of blasphemy (Jude 15)
(14)     Organized Satanic activity (Genesis 6:1–4)
(15)     Promulgation of systems and movements of abnormal depravity (Genesis 6:5, 12)
These conditions prevailed in the days of Noah and they are all rapidly growing again today. There is good reason, therefore, to believe that these present times are those which immediately precede the return of the Lord Jesus Christ.
Morris, Henry M.: The Genesis Record : A Scientific and Devotional Commentary on the Book of Beginnings. Grand Rapids, MI : Baker Books, 1976, S. 172