I'm no English expert. But from what I can tell, it means that people shouldn't go around holding a grudge. If vengeance is to be dealt, God is the one to do it.
Same answer as before. Vengeance was dealt to people who deserved it (bad people), and God was the one who did it. I don't think someone actually took the time to destroy the crops in Egypt for 7 years just for fun.
What's this "namaste" you keep saying btw? I've seen it before, never really got the hang of it. Trying to be cool?