As it was in the days of Noah, so will it be in the days of the Son of man. They ate, they drank, they married, they were given in marriage, until the day when Noah entered the ark, and the flood came, and destroyed them all. Luke 17:26, 27, R.S.V. RC 321.1
It is the nature of sin to spread and increase. Since the first sin of Adam, from generation to generation it has spread like a contagious disease. While the world was yet in its infancy, sin became fearful in its proportions. Hatred of God's law, and, as the sure result, hatred of all goodness, became universal. God, who had created man and given him with an unsparing hand the bounties of His providence, was dishonored by the beings He had created, slighted and despised by the recipients of His gifts. But though sinful man forgot His benevolent Benefactor, God did not forget the creature He had formed. Not only did He send “rain from heaven, and fruitful seasons,” filling man's heart with “food and gladness,” but He sent him also messages of warning and entreaty. Man's wickedness was fully set before him, and the result of transgressing the divine law. RC 321.2
In the days of Noah, the wickedness of the world became so great that God could no longer bear with it.... But He pitied the race, and in His love provided a refuge for all who would accept it. He gave the message to Noah to be given to the people: “My spirit shall not always strive with man.” ... The Spirit of God continued to strive with rebellious man until the time specified had nearly expired, when Noah and his family entered the ark, and the hand of God closed its door. Mercy had stepped from the golden throne, no longer to intercede for the guilty sinner. RC 321.3
All the men of that generation were not in the fullest sense of the term heathen idolaters. Many had a knowledge of God and His law; but they not only rejected the message of the faithful preacher of righteousness themselves, but used all their influence to prevent others from being obedient to God. To everyone comes a day of trial and trust. That generation had their day of opportunity and privilege while Noah was sounding the note of warning of the coming destruction; but they yielded their minds to the control of Satan rather than of God, and he deceived them, as he did our first parents. He set before them darkness and falsehood in the place of light and truth; and they accepted his sophistry and lies, because they were acceptable to them, and in harmony with their corrupt lives, while truth that would have saved them was rejected as a delusion. Numbers were not on the side of right.—The Signs of the Times, April 1, 1886. RC 321.4