Alright, what better way to spend a long weekend than by analyzing Genesis chapter 6? I can think of nothing. :)
So now we are past the genealogy of chapter 5, and the older, obscurer stories about Adam and Eve and Cain and so forth. In fact, in a certain fashion the genealogy acts as a conclusion and recap of those older stories, as it points out in 5:1, "This is the book of the generations of Adam.". Also note that since the genealogy goes from Adam to Noah, it can be thought of as a transition from the life and events of the former (which encompasses Cain/Abel/Seth who are his sons) to the events of the latter, which is primarily about the flood.
Chapter 6, then, begins very logically with describing the background events that precipitated the flood (uhh, pun not intended), and from there describes the story as it transpires. One thing to note is that I don't get the same sense of elided content here that I did in the earlier chapters. While there are certainly gaps in time, the difference is that here the gaps are noted, while in the earlier chapters it seems that certain things are just omitted completely (such as who are the people that Cain feared and where they came from). So there is definitely a tonal shift, which can be explained in a couple different ways, but I won't go into more detail as the story itself merits plenty of discussion.
The first thing I will discuss is right at the beginning, this whole deal with the "sons of God" and "daughters of men" and so on. Once again this is a highly debated subject, so I will perforce just offer a brief overview. Much of the debate is around the identity of the "sons of God", with the most well-known theory that they are fallen angels (i.e. devils) who came to the earth, had sex with mortal women, and this resulted in half-human, half-angel children who are here called the "Nephilim". Here I am going to quote Wikipedia which gives a solid overview of the issue at hand:
In 1 Enoch and Book of Jubilees the Genesis 6 text was developed into a complicated mythology of fallen angels. The 3rd century BC Book of Enoch turns the "sons of God" into fallen angels, referred to as Watchers, who came to earth and had children with human women, resulting in a race of half-angel, half-human beings known as the "Giants" (Nephilim). The view is found in Philo and in Josephus Antiquities 1:73 (or 1:3.1).In the 1st century CE Rabbi Shimeon ben Yochai pronounced a curse on any Jew teaching the Enochite interpretation, and, later Trypho the Jew rejected the interpretation. This was followed by Rashi and Nachmanides. Some commentators on Luke 20:34-36 believe that Jesus was also familiar with the Enochic interpretation, and can be counted with Shimeon ben Yochai, since Jesus rejected that angels could marry and in the same passage equated the "sons of God" with humans.
So this is actually a historical interpretation, dating back several thousand years and many people still believe it today. I can see why this approach might be popular with (orthodox) Jewish scholars, just purely based on analyzing this passage in isolation but things are more complicated if you also include the NT as canonical, because as Wikipedia notes, Jesus states in the book of Luke that angels are "neither married nor given in marriage", which has the obvious implication that they are either incapable or unwilling to have sex. Beyond that, there are other obvious (and unanswered) questions about the nature of angels and that, if they are non-physical beings, how sex could even be possible for them with physical humans. These points are not addressed in the bible (in fact, the true nature of angels can only really be derived by inference as there are very few direct statements about angels made anywhere in the bible).
I should add that some individuals proffer some very elaborate theories about the Nephilim and suggest that some of the "spirits of the Nephilim" survived the flood, becoming either modern-day demons (i.e. evil spirits that inhabits the souls of men and take over control of their bodies) or have somehow reformed their bodies and attempt to control world events by entering positions of power. To the best of my knowledge, none of these theories are supported by any biblical evidence or reasoned analysis. This does not prove them false, but it does render them almost completely apocryphal, hence my skepticism.
What is clear from this passage, however, is that "the LORD saw that the wickedness of man was great on the earth, and that every intent of the thoughts of his heart was only evil continually." This is the genesis of the flood (pun not intended... again). We already saw this process of gradually increasing wickedness displayed by the generations of Cain and now we see the wickedness come to fruition in what is described here, the complete depravity of man (I do not mean this in a Calvinist sense).
When we see the LORD grieved in the next verse, and that this grief results in him wanting to wipe out man from the earth, it really raises a lot of deep issues that I don't have time to address. I will mention the issues so that an interested reader can find out more, but I won't offer a full discussion. The most immediate is the question of whether natural disasters are the result of man's sin. What the flood makes clear is that it is possible, but it offers no convincing evidence (in my opinion) that every natural disaster results from wickedness. This is especially the case when you consider the particular structure of the OT and it's repeated emphasis on material blessings and curses related to obedience, which largely subsides into the NT.
Next is the broader and subtler question of why the men are turning to "only evil continually". This is obviously a very strong expression and it's not clear to me why they have turned to evil like this, why they have turned to evil, and what (if any) core differences exist between the people of that time and people now. In the broadest sense, is it really an intrinsic human characteristic to turn to evil?
Lastly, and perhaps the most subtle of all, is why does the evil of men's hearts cause grief to God, such that he would be *sorry he created man*? Once again it is using very strong language, and while at first glance my question might seem tautological, I do think there is substance here. In particular, I think it raises the question, well, "why did God create man", such that these actions and thoughts of men would cause him to regret his creation? These are substantive issues, but I have other things to talk about for this chapter, so I will say no more.
An exception is found: Noah. What could be in the heart of a man so that he is the single named exception for the pervasive wickedness that is described in the preceding verses? This, too, is not addressed. But what we know is that it's possible to live righteously even in dark times, and also it says that Noah walked with God. So in my opinion the key is walking with God (partnership, unity, shared experience).
God then announces there will be a flood to wipe out the wicked from the earth, and gives Noah astonishingly detailed instructions on how to construct the ark. To my recollection, this is the first place in the bible where we see the word "cubit" (it won't appear in all translations, some will change it out for imperial or metric units). The cubit is a Hebrew unit of distance, which is approximately 1.5 feet. But more important than the numbers is the shift in tone we are seeing. As we get further into the Pentateuch, especially Exodus/Deuteronomy, you will see that specific measurements for the construction of objects is extremely common. In fact, it feels like nearly everything is given measurements. So the existence of measurements of the ark is significant to me in that it thematically relates it to the later construction of the tabernacle, ark of the covenant (how interesting, it's the same word), and various utensils and structures for the Holy Place. Since Noah is here given direct prescriptions for how to construct the ark, and it leads to the salvation of his life, so is later Moses given prescriptions for how to construct the holy objects, which leads to the covenant and the salvation of his people. Just as Noah is chosen from amongst all the people in the world, so is Israel chosen from amongst all the nations of the world.
I think the life of Noah can partially be thought of as foreshadowing the covenant with Israel, but more broadly I think it helps to establish a pattern for how God operates in the world. This is only one example so it doesn't (and can't) show the full pattern, but it shows us part: it shows us that God will not forget the people who walk with him, and that even if the entire rest of the world turns to evil, he works out the salvation of those who follow him. That's what I see in the story of Noah.
That's all I have to say about this chapter. The story continues in chapter 7, so more will be spoken about it then.