An introduction to the idea of a mission statement is given here . A family mission statement should include what the family does for its members, and what the members together do for others. Howver, some congregations take on specific missions, such as a soup kitchen, a clothing ministry, or the like. Evangelizing the unchurched is another potential outward-looking mission. In the long term, the congregation that lives only to itself is likely to die to itself.
Some deaneries have intentional missions, such as soup kitchens and other services for the poor.
However, many just meet. It is not always clear what missions are appropriate for a collection of congregations whose main common characteristic is their geography. However, many pew-sitting Episcopalians would not understand this statement, not be able to see signs of it in practice. This is a sad commentary on the leadership of our bishops, rectors, and vicars. Anything less is is a shelling short of the notion that the bishops are today's successors to the Apostles.