Well Mrs. Jones5, it's that feeling of not being alone. But, you brought it up.
Satanas,
Since I'm powerless, you need not fear me, do you? But, if God backs up the warning, that's a different story, isn't it?
Robdar,
Who God chastises and who He doesn't, I have nothing to say about it. I only deliver the message.
Repent from what? The main thing is idolatry. By that I mean, anything we put ahead of God is an idol (whether it be money, work, houses, clothes, people, sports and recreation, drugs and alcohol, etc.) God is to be first in our lives.
Gosh, there's a multitude of things we need to turn away from, including rebellion against God, pride, greed, anger, etc.
What happens if we repent? We are spared like Nineveh. What happens if we refuse to heed? We are chastised.