The structure of verse 12 is A-B-B′-A′, in which A stands for a statement about the earth, and B stands for a statement about corruption.

And God saw the earth: saw repeats the thought of “in God’s sight” in verse 11. In some languages saw may suggest only a momentary awareness. Here the thought is that God has looked on the wicked condition of humanity, and as a result he is ready to make a decision to destroy the earth. Accordingly Good News Translation gives a better model for some languages: “God looked at the world and saw…”; or as a dependent clause, Bible en français courant has “When he [God] looked at the earth….” Earth now refers to both the physical world and the people in it, but with emphasis upon the wicked condition of people, which is the focus in the second half of the verse.

And behold, it was corrupt: behold calls attention to the consequence of God’s looking at the earth and may be translated by a word equivalent to “truly, indeed.” Corrupt, used twice in this verse, is the same word as in verse 11.

Examples of the way some translations render the first half of the verse are “God looked at the world, he saw that it had become completely bad…” and “He saw bad conduct rising in every part of the world.”

For all flesh had corrupted their way: for introduces the reason for the previous clause. All flesh includes all living beings, and so some interpreters hold that the animals are included in the wicked condition of the earth. However, here the context is departure from right conduct, and so flesh must refer exclusively to human beings. It is also significant that throughout the Old Testament the subject of violence is always people and never animals. Their way refers to conduct, the way the people lived. The full expression may be translated, for example, “They were living evil lives” or “They were living in the wrong way.” Bible en français courant says “Everyone had gone astray.” One translation that joins this half of the verse to the first half says “… as a result of the useless behavior of all the people.” Another continues the thought of God seeing what was happening, with “He didn’t see one good tribe [or, group]. No. Every tribe [group] was working at doing only bad things.”

Upon the earth, which parallels earth in the first part of this verse, serves to make the statement of corruption true everywhere. Since this thought is expressed in the first part of the verse, some translations do not repeat it here.

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .