Americans like to dream big. When we are kids, people ask us "what do you want to be when you grow up?" and we are expected to say things like Doctor or Lawyer or Astronaut or even President. As adults, we are told to try and get ahead and seek that promotion or achieve more in our professional life. There is constantly competition to win or score or be recognized.
Even in ministry this is true. Pastors are often, sadly, judged by the size of their churches. If you have a large church you must be good. If you have a small church you must be bad or even that you don't have the blessing of God. This way of thinking has hurt me over the years and driven me to seek after numbers rather than just to be faithful in my work as a minister of the gospel.
In 1 Thessalonians 4 Paul gives people this advice "make it your ambition to lead a quiet life: You should mind your own business and work with your hands, just as we told you, so that you may win the respect of outsiders."
As I have gotten older, I have changed my goal in life and in ministry. My goal is now to be faithful. Am I loving? Am I kind? Am I serving? Am I giving? I don't expect results but thank God if they do come.
What is your ambition? My advice is to seek the Lord and seek to be faithful...that's it. Everything else is just gravy.