CHAPTER 6 Jan. 3 
The Background to the Flood 
It happened that when men began to multiply on the surface of the land, and daughters were born to them, 2that the sons of God saw that the daughters of men were beautiful, and they took for themselves wives of all that they chose. 3Yahweh said, My Spirit will not strive with man forever, because he also is flesh; yet will his days be one hundred twenty years. 4There were aggressive men [Nephilim] in the earth in those days, and also after that, when the sons of God came in to the daughters of men, they bore children to them. Those were the mighty men who were of old, men of renown. 5Yahweh saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually. 6Yahweh was sorry that He had made man on the earth, and it grieved Him in His heart. 7Yahweh said, I will destroy man whom I have created from the surface of the ground; man, along with animals, creeping things, and birds of the sky; for I am sorry that I have made them. 8But Noah found favour in Yahweh’s eyes.
God’s Relationship with Noah 
9This is the history of the generations of Noah. Noah was a righteous man, blameless among the people of his time. Noah walked with God. 10Noah became the father of three sons: Shem, Ham, and Japheth. 11The earth was corrupt before God, and the earth was filled with violence. 12God saw the earth, and saw that it was corrupt, for all flesh had corrupted His way on the earth. 13God said to Noah, The end of all flesh has come before me, for the earth is filled with violence through them. Behold, I will destroy them with the earth. 14Make a ship of gopher wood. You shall make rooms in the ship, and shall seal it inside and outside with pitch. 15This is how you shall make it. The length of the ship will be three hundred cubits, its breadth fifty cubits, and its height thirty cubits. 16You shall make a roof in the ship, and you shall finish it leaving a cubit between the roof and the sides. You shall set the door of the ship in its side. You shall make it with lower, second, and third levels. 17I, even I, do bring the flood of waters on this earth, to destroy all flesh having the breath of life from under the sky. Everything that is in the earth will die. 18But I will establish my covenant with you- you shall come into the ship, you, your sons, your wife, and your sons’ wives with you. 19Of every living thing of all flesh, you shall bring two of every sort into the ship, to keep them alive with you. They shall be male and female. 20Of the birds after their kind, of the livestock after their kind, of every creeping thing of the ground after its kind, two of every sort shall come to you, to keep them alive. 21Take with you of all food that is eaten, and gather it to yourself; and it will be for food for you, and for them. 22Thus Noah did. According to all that God commanded him, so he did.

Commentary

6:2 “Sons of God” is used concerning men, especially those who know the true God (Deut. 14:1; Hos. 1:10; Lk. 3:38; Jn 1:12; 1 Jn. 3:1). Lk. 20:35-36 says that the angels do not marry. See on 4:26.
6:3 120 years- Knowing the destruction that would come on all except Noah, God waited in the hope that more would be saved. He as it were hoped against His own foreknowledge that more would BE saved (1 Pet. 3:20). Peter says in 1 Pet. 3:19 that Christ through His Spirit preached to the people of Noah’s day. In 2 Pet. 2:5 he says that Noah was a preacher of, or [Gk.] ‘by’ righteousness to the people around him. Yet in 1 Pet. 3:19 Peter says that Christ preached to those same people through His Spirit. The resolution surely is that although Noah had never met the Lord Jesus, he lived according to the same Godly spirit as did Jesus; and this was his witness to his world. In this sense the spirit or disposition of Christ was found in all the Old Testament prophets (1 Pet. 1:11).
6:4 The Hebrew word for “aggressive men” or “giants” in Gen. 6:4 is also used to describe the sons of a man called Anak in Numbers 13:33. Freak human beings of unusual size or strength are sometimes born today, but it does not mean that their parents were angels. We are not specifically told that these men were the children of the “sons of God”. “There were aggressive men…and also after that…the sons of God came in to the daughters of men”. 
6:5 The days of Noah are a type of the last days of AD70, and of the last days before Christ’s return: “As the days of Noah were, so shall also the coming of the son of man be” (Mt. 24:37).