6:4 giants. These “giants” were the monstrous progeny of the demon-possessed men and women whose illicit activities led to God’s warning of imminent judgment. The Hebrew word is nephilim (“fallen ones”), a term possibly relating to the nature of their spiritual “parents,” the fallen angels. That they were also physical giants is evident from the fact that the same word is later used in connection with the giants in Canaan at the time of Joshua (Numbers 13:33) and by the fact that the word here was translated in the Septuagint by the Greek word gigantes.
6:4 also after that. “After that” clearly refers to Numbers 13:33 and probably represents an editorial insertion in Noah’s record by Moses. These giants in Canaan may also have had demonically-controlled parents; they were also known as the Anakim, the sons of Anak.
6:4 daughters of men. The idea that these “daughters of men” were actually descendants of Cain, and the “sons of God” descendants of Seth has been a widely held Christian naturalistic interpretation. This was not the intended meaning of the writer, however, who could certainly have written that the male descendants of Seth began to take wives from the daughters of Cain if that were his meaning. The descendants of Seth were not “sons of God” (most of them perished in the Flood) and the female descendants of both Cain and Seth were certainly “daughters of men” (literally, daughters of Adam). Besides, Adam had many other sons in addition to Cain and Seth. Further, even though intermarriage between believers and unbelievers is wrong, it could not in itself have produced universal wickedness and violence.
6:4 men of renown. The antediluvian giants had, by the time of Moses, become renowned heroes of antiquity, as far as the world was concerned. They, like their parents, were probably demon-controlled, their giant stature engineered by genetic manipulations discovered and carried out by these evil spirits. They could not have been demi-gods (half man, half “god”), however, as ancient mythology claims, since such imaginary beings are beyond the pale of God’s creative purposes. Fallen angels are not prospects for salvation, whereas fallen men and women are. A half-angel, half-human being would be an impossible anomaly, in terms of soteriology. The only apparent solution to all the problems posed by these verses is demon possession of both parents and progeny, not demonic marriage or procreation.