Genesis 6:1-8
In the days that were before the flood they were ... marrying and giving in marriage, until the day that Noe entered into the ark. Matthew 24:38.
In Noah's day brute force was the prevailing influence in the world. By threatened punishment, men intimidated other men.60Manuscript 29, 1911.
Instead of doing justice to their neighbors, they carried out their own unlawful wishes. They had a plurality of wives, which was contrary to God's wise arrangement. In the beginning God gave to Adam one wife—showing to all who should live upon the earth, his order and law in that respect. The transgression and fall of Adam and Eve brought sin and wretchedness upon the human race, and man followed his own carnal desires, and changed God's order. The more men multiplied wives to themselves, the more they increased in wickedness and unhappiness. If one chose to take the wives, or cattle, or anything belonging to his neighbor, he did not regard justice or right but if he could prevail over his neighbor by reason of strength, or by putting him to death, he did so, and exulted in his deeds of violence. They loved to destroy the lives of animals. They used them for food, and this increased their ferocity and violence, and caused them to look upon the blood of human beings with astonishing indifference.61Spiritual Gifts 3:63, 64.
The descendants of Seth were called the sons of God; the descendants of Cain, the sons of men. As the sons of God mingled with the sons of men, they became corrupt and, by intermarriage with them, lost, through the influence of their wives, their peculiar, holy character, and united with the sons of Cain in their idolatry. Many cast aside the fear of God and trampled upon His commandments. But there were a few that did righteousness, who feared and honored their Creator. Noah and his family were among the righteous few.62The Story of Redemption, 62.
Polygamy was practiced at an early date. It was one of the sins that brought the wrath of God upon the antediluvian world.... It was Satan's studied effort to pervert the marriage institution, to weaken its obligations and lessen its sacredness; for in no surer way could he deface the image of God in man and open the door to misery and vice.63Patriarchs and Prophets, 338.
From Conflict and Courage - Page 36
Conflict and Courage