The predominant idea which emerges clearly from this text is that a new stage has been reached in the evolution of evil in the early civilizations of man. We shall see that this is in fact the prelude to the great flood, which becomes the greatest judgement of God on earth apart from that which is to be when Christ returns.
From Chapter 3 onwards we read of much trouble as man, as a result of his willful disobedience against God is driven out of the garden of Eden. Cain, the son of Adam kills his brother Abel out of jealousy. This becomes the record of the first murder. Chapter 4 records that Cain went away from the presence of God and settled in a restless land. His grandson Lamech begins a new habit of polygamy and he also commits murder. In Chapter 5 we read of a line of men who walked with God, and who are found in the ancestry of our Lord Jesus, but we read of their death. Truly, the emergence of sin has brought lack of peace and death into the world. A pattern of self- destruction has emerged in the world.
Chapter 6 creates an additional dilemma, which we shall consider now.
THE SONS OF GOD MARRY THE DAUGHTERS OF MEN ( vv. 1&2)
The beginning of the end of this civilization happens when the sons of God look to the attractive daughters of man and take them as their wives. This clearly had a negative effect upon them and this is affirmed in Genesis 6: 3 and 5-7.
But who are these sons of God and who are these daughters of man ?
The view that held by some early church fathers such as Justin Martyr, Tertullian, Cyprian and Ambrose, was that this referred to an intermarriage between angels and human beings. The reason why they thought this was that this phrase, ‘sons of God’ almost always refers to angels in the OT  and so the thought arose that these must have been angelic beings that married human beings. They thought for instance of the angels, who appeared to Abraham, warning him that Sodom (proverbial for its great sin of sodomy - Gen. 18:20; 19:5) was about to be destroyed by God. They thought of these three angels that appeared as ordinary looking men, to be demonic types of those that might have misled the daughters of man.
Against this view there are two weighty arguments. Firstly, there is no specific reference to angels in Genesis 6. In fact, there is no reference to angels at all in the first 6 chapters of Genesis. Secondly, the Lord Jesus tells us in the synoptic gospels that the angels do not marry because they are eternal beings who do not propagate. So, these are strong reasons for rejecting that particular view.
The plainest explanation is that these were marriages taking place between the seed of God and the seed of Satan, based upon that pivotal division found in Genesis 3:15, as we have consistently argued in our previous expositions of Genesis. The godly line through Seth, based on divine election, are the sons of God. It is these sons of God that make this very poor choice, to take as wives the attractive daughters of man (singular) - that is, of the descendants of the man Cain, who walked away from the presence of God. God has a word on this matter. Before we get to some specific observations with regard to this in Genesis 6, we must point out that the first five books of Moses as a whole, provide numerous warnings of God against any intermarriage of believers and unbelievers. In this regard we need to remember Genesis 26: 34,35, the marriage of Esau to a ‘Cainite/ Hittite‘ woman (i.e. a wife not taken from the godly seed), a fact that made life for his parents Isaac and Rebekah bitter.
We also think of the story of Dinah, the daughter of Jacob and Leah who was raped by Shechem the Hivite in Genesis 34. The rape of Dinah by Shechem was enough cause for revenge on behalf of Jacob’s sons, but it was the fact that Shechem was uncircumcised, and not a son of the covenant (Gen. 34:14) and daring to make a marriage proposal to Dinah for marriage, that sent Jacob’s sons, Simeon and Levi into a murderous frenzy! There are other such illustrations, and the point is, that the intermarriage between the people of the line of Seth and the line of Cain, the sons of God and the daughters of man are not encouraged in the Bible.
So what was happening here in Genesis 6? Moses indicates that after the multiplication of man on the earth (6:1) the sons of God, the line of Seth, were rebelling against God. The way in which they expressed that rebellion was by taking as their wives any they chose among the daughters of man. In plain language, the appearance of the beauty of the women of Cain overruled the sense of the spiritual judgement of the sons of Seth. Hormones overruled the godly heritage.
God’s displeasure with this is clearly seen in 6:3. It is very clear that God is not angry with angels who did this! No! The judgement here will not be against angels, but against man! God is angry with the sons of God, born in the line of Seth, because they were compromising their godly heritage! God is angry with the daughters of man for being seductive and subversive of His rule.
At this time there was as yet no written law, but the fact was that this law of ‘holiness unto the Lord in marriage relationships’ (Gen. 2:24,25) was written on the hearts of the sons of God. And once the law was given to Moses at Sinai this fact is established and upheld in the time of Ezra when this problem is addressed in Ezra 9. Right through the Old Testament God forbade his people to marry those who were not his people, and the same principle continues right down into the New Testament. We that are in Christ are instructed to marry only in the Lord. (1 Cor. 7:39)
So, the first question for a son of God with respect to a prospective marriage partner is not, ‘is she beautiful ‘, but ‘is she godly’ ? Sadly, many Christian sons and daughters have pierced themselves with grief because they have entered into an ungodly marriage, because beauty and physical attraction and chemistry and need are very powerful impulses working upon their fallen minds and hearts.
At the heart of this great problem that arises in Genesis 6 is this problem of indiscriminate sexual attraction and activity  It is significant that Jesus linked this event with Matt. 24:37: “As it was in the days of Noah, so shall it be in the days of the coming of the Son of Man”. Is this world wide focus on rampant perverse and illegitimate forms of sexuality the indicator of our Lord’s soon return?
Indiscriminate sexuality (i.e. forbidden forms of sexuality) is the main cause whereby marriages and families are destroyed. It is ultimately the cause why a society or a civilization is destroyed. This early generation is destroyed because of unrestrained sexual desires; Sodom and Gomorrah are destroyed on the same account; Paul’s analysis of the nature and development of sin in Romans 1 :18ff follows the same line of reasoning - unnatural unrestrained sexual relations are the reason why God destroys a society, and the final handing over of a society is when God hands men and women over to dishonourable passions (Rom.1:26).
As one looks at the condition of our own society, one looks with great concern at the spread and acceptance of the homosexual life style. We look with great concern at the fragility of so many marriages, and one can’t help but thinking that many marriages are fragile because they are built on an improper foundation. Many people marry for the wrong reason. They marry because they are lonely or infatuated or madly in love. But these things do not sustain a marriage when the temptations of life arise, such as when children come and when romantic evenings go out of the window! Marriage is not firstly a feeling. It is a theological thing, because God created marriage (Genesis 2). There must be a God centred purpose, a commitment to biblical companionship in marriage. A marriage may be begun with the grandest of wedding feasts and with a romantic get- away as a honey moon,with everyone excited, but it is not going to last,and the cracks appear very quickly if there is no commitment to the basics that God has designed for a successful marriage.
GOD’S RESPONSE - A WORD OF WARNING TO THAT GENERATION.
We are told, “Then the LORD said, “My Spirit will not abide (contend) with man for ever, for he is flesh ; his days shall be 120 years.” (v.3).
In vv. 5-7 he elaborates on this fact and we shall consider this next time.
God saw what was happening to the people that He had made. They were brilliant people, made in His image. They were accomplished in poetry and song and skilled musicians. They were skilled workers of metal and bronze; pastoralists and agriculturalists (Gen. 4). The women were beautiful and some of the men were impressive giants (the meaning of Nephilim ). And yet they all fell short of God’s glory – the glory that He had designed for them from the beginning of the world, except for the sin which they freely chose! God saw all this and He saw how man was developing and He was unimpressed and so He decreed that, “Man is flesh; his days shall be 120 years” (6:3). We note, that man now lives substantially shorter than the first patriarchs mentioned in Gen. 5.
It was, of course not God’s desire that any of them should perish but that all should turn from their sin and live. He took no pleasure in their deaths. He spoke to their consciences, and he addressed them personally through preachers like Enoch and Noah. He was good to His creatures. He was patient with them, and we are reminded of the words of Peter that “God waited patiently in the days of Noah while the ark was being prepared ” (I Pet. 3:20). That is the nature of our God. He is patient and longsuffering with us. He hasn’t given up on us. He is still working with us . He is still preaching to us .
But He will not abide or contend with men forever, when they go on in their sin. Verse 3 and then verses 5-7 and the next few chapters will show us that. There comes a time when God says, “Enough! You have had heard enough sermons. You have been prayed for enough. A time will come when His Spirit will be withdrawn and God shall speak no more. The Saviour will become our Judge.
Now I don’t know how long God is going to contend with our generation. We have lived under incredible privileges. We have had the full gospel given to us by the appearance of Christ; we have lived under the anointing of the outpoured Holy Spirit, and we have been no more responsive than the sons of God have been in Noah’s day.
The time for the final judgement is approaching. The Lord Jesus is your only refuge. He is your only righteousness. Flee to Him. Abide and live in Him. Amen.
 This view is also held by some modern commentators
 E.g. Job 1:6; 2:1
 Matthew 22: 30 , Mark 12 :25 and particularly Luke 20:34-36
 e.g. Matthew Henry holds to this view
 i.e. the Torah , or Septuagint
 Except if they came into the covenant of God with Israel , e.g. Ruth and Rahab
 Moses himself was guilty of this very thing . His first wife was Jethro’s daughter Zipporah, but Moses took another wife and she was a woman from Ethiopia, a Cushite (Num. 12:1), and it caused division between him and his sister Miriam.