The book of Enoch expands on Gen6:1,2 also alluded to in Jude1:6 concerning angelic or rather satanic union with women and the irretrievable corruption it caused, even extending to the animal kingdom through bestiality. It resulted in the “giants” referred to in verse 4 and testified to in later scripture (e.g.Deut2:21, Num13:32-33 cf. Hebrew interlinear). These offspring of unions between satanic beings and humans occupied the Canaanite territories, a notable being Og, the Amorite King of Bashan famous for his oversized bed (Deut3:11). (No, I never learnt about him in Sunday school either). But these are no more fairy stories than Noah and the Ark: they are Scriptural and archaeological realities, and referred to by some of the very earliest Church Fathers. From these giants came the “unclean spirits” that roamed the world and were prevalent in Jesus’ day. Again the Book of Enoch fills out much of the detail here for it pertains to the Gen6:1 incident concerning the fallen watchers. This polluted seed pool needed to be eliminated, which explains not only the Flood but the wholesale extermination of men, women and children (e.g. Deut3:6) in seven of the Canaanite nations God’s elect people went on to inherit, although some of these demonic hybrids continued up to the time of David (e.g. 1Chron20:4-8 – consult Hebrew interlinear).
But what cannot be perceived without reference to the book of Enoch yet is needed to understand the rationale behind the universal Flood is that these satanic collaborators had imparted knowledge to humanity that the Lord had intended mankind gradually to discover over many centuries. As with Adam and Eve and the forbidden fruit from the tree of knowledge, humanity in its infancy was not ready for the knowledge they provided and it would lead to their destruction, yet could never be unlearnt, hence the need for a radical universal cleansing by water. Enoch19:1 explains that these rebellious sons of God who left their appointed place (cf. Jud1:6) and were responsible for the global contamination and the thwarting of God’s plans for mankind’s development were able to assume different forms to carry out their illicit unions (re: Mt22:30). Through God’s mercy, the bulk of humanity who ignored Noah’s warning and perished in the Flood has subsequently had the good news preached to them by Jesus Himself (1Pet3:19,20). So, the apostle indicates, do all the dead have the opportunity to hear the good news so that although having been punished in the flesh “they might live according to God in the spirit” (1Pet4:6). Some struggle with that concept believing it to undermine the relevance of the gospel. It becomes far more intelligible (indeed right and just) once one understands the context of gospel salvation within God’s broader reconciliatory plans. These imprisoned spirits were given the opportunity to repent and acknowledge Christ’s lordship; they were not to be betrothed as His eternal Bride, nor did they escape punishment for they had been “imprisoned” for centuries. Indeed, some very early Christian writers including Irenaeus understood Adam’s physical death, though partly a punishment, was in effect a concession by which once freed of the body he could be freed from sin so that he could begin again “to live for God”.
Such a principle is alluded to in Gen6:3 – the reference to God’s “spirit” not being the Holy Spirit but the human spirit (cf. Rom8:16) that “does not consistently or rightly adjudicate in view of the flesh” as a result of which man’s life span was shortened for the sake of his eternal wellbeing (cf. Gen6:3). That makes sense in the context of what I in line with the majority of pre-Augustinian Church Fathers regard as the tripartite nature of man: body, soul and spirit. Such an understanding is required to grasp some of Paul’s essential soteriology, in particular his references to the inner conflict of “flesh versus spirit” (not Spirit) – discussed in detail in chapter two of “The Fellowship of the Secret”
YouTube video of Enoch’s account of the fallen watchers HERE