Genesis 6: 5 The Lord saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually.
11 Now the earth was corrupt in God's sight, and the earth was filled with violence. 12 And God saw the earth, and behold, it was corrupt, for all flesh had corrupted their way on the earth.
This is all we are told in Genesis of the pre-flood corruption on earth. Yes, there is mention of the sons of God and the daughters of man, but nothing condemning this. Then we get this:
7 So the Lord said, “I will blot out man whom I have created from the face of the land, man and animals and creeping things and birds of the heavens, for I am sorry that I have made them.”
13 And God said to Noah, “I have determined to make an end of all flesh, for the earth is filled with violence through them. Behold, I will destroy them with the earth
Now, there was no “law” yet, no Ten Commandments. We are told nothing of specifics, nor – at least in Genesis – on what basis such corruption could be identified.
In the Book of Enoch, there are further details. This book, apocryphal for all Christian traditions and denominations except for the Ethiopian Orthodox Church, begins by describing the judgment coming on all the earth, except for the elect who will be saved.
In chapter 6, we are told that the act of angels taking the daughters of men was known to be a sin…a sin by the angels!
And it came to pass when the children of men had multiplied that in those days were born unto them beautiful and comely daughters. And the angels, the children of the heaven, saw and lusted after them, and said to one another: 'Come, let us choose us wives from among the children of men and beget us children.' And Semjaza, who was their leader, said unto them: 'I fear ye will not indeed agree to do this deed, and I alone shall have to pay the penalty of a great sin.'
The angels swore an oath to each other, removing Semjaza’s concern, and then did the deed. But why did this sin by the angels require a punishment of men, wiping them off from the face of the earth? It wasn’t this sin, but another, described in the earlier chapters, 2 – 5. First, the purpose of each aspect of creation is described:
· Observe ye everything that takes place in the heaven, how they do not change their orbits, and the luminaries which are in the heaven, how they all rise and set in order each in its season, and transgress not against their appointed order.
· Behold ye the earth, and give heed to the things which take place upon it from first to last, how steadfast they are, how none of the things upon earth change, but all the works of God appear to you.
· Behold the summer and the winter, how the whole earth is filled with water, and clouds and dew and rain lie upon it.
· Observe and see how (in the winter) all the trees seem as though they had withered and shed all their leaves, except fourteen trees, which do not lose their foliage but retain the old foliage from two to three years till the new comes.
· And again, observe ye the days of summer how the sun is above the earth over against it.
· And you seek shade and shelter by reason of the heat of the sun, and the earth also burns with growing heat, and so you cannot tread on the earth, or on a rock by reason of its heat.
· Observe ye how the trees cover themselves with green leaves and bear fruit:
· And behold how the sea and the rivers in like manner accomplish and change not their tasks from His commandments'.
Every being in creation has a purpose, an order for which these were created. Chapter 5 explains this: