People living after the Flood, up to today, have the same sinful nature. As much as evolutionists would like to argue the point, humanity has not improved.
It would be difficult to devise a sentence that would more effectively portray the corruption of humanity than does Genesis 6:5. Mankind was totally depraved.
God in us by His Spirit accounts for any real good that we may do. Otherwise, we would be just like everyone else: altogether evil continually.
The elect are not immune to antinomian deception, including the doctrine of eternal security, the total depravity of man, unconditional love, and cheap grace.
When Adam and Eve were given the death sentence by God, they also received hope that through the offspring of Eve a Savior would be born to crush the serpent.
Progressives tend to believe that human nature is perfectible and evolving. Conservatives tend to believe that human nature is evil and must be controlled.
If we allow doctrine to be contaminated with man's flawed reason, it will defile the truth. Job's friends used profane sources in their arguments.