It is also a preview of the theme of humility and submission to God that forms the core of chapter 4. The key is humility. When we're in the midst of a political season we can get pretty cynical. First, I don't believe that ambition itself is a bad thing. If we didn't aspire to something better, something higher, no progress at all would be made in society.
Ambition is a dogged persistence towards a goal to accomplish something.
We are ambitious for our families, to make a better life for them. We are ambitious for noble causes of all kinds. We should be ambitious for God, to see his Kingdom come on earth as it is in heaven. Ambition is essential. Ambition is a good thing.