This verse repeats the thought of verse 13, so that the only thing new here is in the opening few words. Behold, as in verse 13, introduces the decision to destroy life with a flood. See verse 13 for comments.
Although the story has already made clear that the destruction is to be by means of a flood (for example, from the instructions to build a boat), the word for flood occurs here for the first time. Flood of waters is an expression used only in relation to Noah’s flood. The verb form meaning “to flow” is found in Isa 30.25 (“running with water”); 44.4 (“flowing streams”). Bring a flood reflects the Hebrew manner of expression, which represents the action spoken from the point of view of the earth. Good News Translation “send a flood on the earth” is spoken from a point of view outside the earth. In some languages it will be necessary to say “I will cause the earth to flood” or “I will make a flood on the earth.”
Some languages do not have a term for “flood”; and in many languages a “flood” is little more than the seasonal overflow of a river due to heavy rains or melting snow. In some cases a verb form is used, that is, “the water flowed outside the river.” In our text the flood is destructive, and this element must often be stated; for example the flood may be qualified as “the flood that destroys” or “the big waters that drown people.” Among coastal people the term for “tide” has sometimes been extended in meaning to refer to floods on land. In some other cases the term for a large body of water such as a river or lake has been used with verbs to indicate that the water flows over the top of the land. One translation says “I will make a huge river of water come on the world to drown everything that lives….”
To destroy all flesh: destroy is the same verb as used in verse 13. All flesh, which is the same as in verse 13, now takes on a more inclusive sense, since it includes both human beings and animals. The inclusion of animals is made clear by the qualifying expression in which is the breath of life. See Gen 1.30. Here the expression is literally “the ruach of life,” and it refers to “every living being” (Good News Translation) or “everything that lives” (Bible en français courant).
From under heaven (literally “under the sky”) indicates the extent of the destruction. This is added to emphasize the completeness of the destruction. We may say with Biblia Dios Habla Hoy “I am going to send a flood that will cover the earth and destroy everything that has life in every part of the world.”
Everything that is on the earth repeats and makes emphatic the totality of the destruction. Shall die is a verb that is used six times in Genesis, but elsewhere it is used mostly in poetic contexts with the sense of “to pine away, languish.” Here the meaning is to “perish” (poetic in current English), or “die.”
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 .