God gave Noah a sign, or token, to show that He would never cause another world wide flood. Everytime you see the rainbow after the rain, it is God's sign that He will never destroy the earth with a flood. Men were violent and they disobeyed God's commands. They were exceeding wicked. Things have not changed today.
Men are still violent and wicked.
We do not want to be destroyed with wicked men. We want to live with the LORD God. If we fear God and serve Him we will be saved from the fire. We must repent of our sins. That means we must admit that we are sinners and that we want to live God's way.