England expects that every man will do his duty

This is an old saying that means that in England (a country with a long history), everyone is expected to do their job and help out when it is needed. It's like when you are playing with your friends and you all have to work together to finish a big project. Everyone has their own job and if they do it well, then the project will be successful. In England, it means that everyone has to work hard and do their part to make sure things go well for the country.