The opening verses to the flood story are central to its interpretation. The initial statement about the human situation (6:5) provides the rationale for what follows: the great wickedness of humankind and the evil inclinations of the human heart. The words only, every, and continually specify the depth and breadth of human sinfulness. Genesis 6:11-13 will lift up the "violence" of human beings in particular. Notably, the flood story concludes with essentially the same description of the human race (8:21). In other words, the flood did not have any effect whatsoever on the sinfulness of humankind. God makes a decision to continue with the world even without any human change; the world's future will depend upon God's promises.
The basic character of the human heart is set alongside the response of the divine heart (6:6). God appears not as an angry and vengeful judge, but as a grieving and pained parent, distressed over what has happened. The NIV translation says it best: God's "heart was filled with pain." These remarkably expressed divine emotions, which issue in a decision to destroy all living things (6:7), are resolved on the side of mercy in God's choice of Noah and his family.
God's regretful response to human sin assumes that human beings have successfully resisted God's will for the creation. Such language thereby reveals that the flood was not planned by God, but was a divine response to human sin and its disastrous effects on the creation.
5 The Lord saw that the wickedness of humankind was great in the earth, and that every inclination of the thoughts of their hearts was only evil continually. 6And the Lord was sorry that he had made humankind on the earth, and it grieved him to his heart. 7So the Lord said, I will blot out from the earth the human beings I have createdpeople together with animals and creeping things and birds of the air, for I am sorry that I have made them.
New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org