WBCのウェンナムのGen8:21該当箇所、コピペします。参考までに。
“for the ideas of man’s mind are evil from his youth.” Though the statement is not as severe as 6:5, note the omissions: “every (idea),” “nothing but (evil)” are omitted, while “from his youth” replaces “all the time.” There can be no doubt that man’s nature has not changed since before the flood. The milder language simply reflects his creator’s more lenient attitude after the flood. R. W. L. Moberly (At the Mountain of God, JSOT SS 22 [Sheffield: JSOT Press, 1983] 89–93, 113–15) has noted a similar example in Exod 33:3; 34:9 of a reason for divine judgment, “for you are a stiff-necked people,” being subsequently cited as a justification of his mercy.
The striking similarity between the flood and Sinai, between Noah and Moses, is of great theological significance for the interpretation of each story.… The world, while still in its infancy, has sinned and brought upon itself Yahweh’s wrath and judgment. Israel has only just been constituted a people, God’s chosen people, yet directly it has sinned and incurred Yahweh’s wrath and judgment. Each time the same question is raised. How, before God, can a sinful world (in general) or a sinful people, even God’s chosen people (in particular), exist without being destroyed? Each time the answer is given that if the sin is answered solely by the judgment it deserves, then there is no hope. But in addition to the judgment there is also mercy, a mercy which depends entirely on the character of God and is given to an unchangingly sinful people.
Wenham, Gordon J.: Word Biblical Commentary : Genesis 1-15. Dallas : Word, Incorporated, 2002 (Word Biblical Commentary 1), S. 190