And God looked upon the earth, and, behold, it was corrupt; for all flesh had corrupted his way upon the earth.

Wesley's Notes

6:12 God looked upon the earth - And was himself an eye - witness of the corruption that was in it, for all flesh had corrupted his way - It was not some particular nations that were thus wicked, but the whole world so; there was none good beside Noah.

Matthew Henry's Concise Commentary

6:12-21 God told Noah his purpose to destroy the wicked world by water. The secret of the Lord is with them that fear him, Ps 25:14. It is with all believers, enabling them to understand and apply the declarations and warnings of the written word. God chose to do it by a flood of waters, which should drown the world. As he chooses the rod with which he corrects his children, so he chooses the sword with which he cuts off his enemies. God established his covenant with Noah. This is the first place in the Bible where the word 'covenant' is found; it seems to mean, 1. The covenant of providence; that the course of nature shall be continued to the end of time. 2. The covenant of grace; that God would be a God to Noah, and that out of his seed God would take to himself a people. God directed Noah to make an ark. This ark was like the hulk of a ship, fitted to float upon the waters. It was very large, half the size of St. Paul's cathedral, and would hold more than eighteen of the largest ships now used. God could have secured Noah without putting him to any care, or pains, or trouble; but employed him in making that which was to be the means to preserve him, for the trial of his faith and obedience. Both the providence of God, and the grace of God, own and crown the obedient and diligent. God gave Noah particular orders how to make the ark, which could not therefore but be well fitted for the purpose. God promised Noah that he and his family should be kept alive in the ark. What we do in obedience to God, we and our families are likely to have the benefit of. The piety of parents gets their children good in this life, and furthers them in the way to eternal life, if they improve it.

Matthew Henry's Whole Bible Commentary

Verses 11-12

The wickedness of that generation is here again spoken of, either as a foil to Noah's piety-he was just and perfect, when all the earth was corrupt; or as a further justification of God's resolution to destroy the world, which he was now about to communicate to his servant Noah. 1. All kinds of sin was found among them, for it is said (v. 11) that the earth was, (1.) Corrupt before God, that is, in the matters of God's worship; either they had other gods before him, or they worshipped him by images, or they were corrupt and wicked in despite and contempt of God, daring him and defying him to his face. (2.) The earth was also filled with violence and injustice towards men. There was no order nor regular government; no man was safe in the possession of that which he had the most clear and incontestable right to, no, not the most innocent life; there was nothing but murders, rapes, and rapine. Note, Wickedness, as it is the shame of human nature, so it is the ruin of human society. Take away conscience and the fear of God, and men become beasts and devils to one another, like the fishes of the sea, where the greater devour the less. Sin fills the earth with violence, and so turns the world into a wilderness, into a cock-pit. 2. The proof and evidence of it were undeniable; for God looked upon the earth, and was himself an eye-witness of the corruption that was in it, of which before, v. 5. The righteous Judge in all his judgments proceeds upon the infallible certainty of his own omniscience, Ps. 33:13. 3. That which most aggravated the matter was the universal spreading of the contagion: All flesh had corrupted his way. It was not some particular nations or cities that were thus wicked but the whole world of mankind were so; there was none that did good, no, not one besides Noah. Note, When wickedness has become general and universal ruin is not far off; while there is a remnant of praying people in a nation, to empty the measure as it fills, judgments may be kept off a great while; but when all hands are at work to pull down the fences by sin, and none stand in the gap to make up the breach, what can be expected but an inundation of wrath?