Every church has a mission which is guiding it. This might not be a stated or even known mission, nonetheless it is a mission. A mission is most simply defined as what a church does. Along with the mission are values which a church holds. Once again these are both spoken and unspoken. Thrown in with the mission and values is the vision, what is the next step for the church in accomplishing the mission. These three work together, but they do not ensure movement to the mission.
For example, a church could be following all the values with great excellence, and still not accomplishing the mission. Without noticing a church can elevate the values ahead of the mission. When there is a diffusion of the mission focus, there needs to be a focus, that is usually on the values. Now not all people hold the same level of importance on all the same values. The tendency is to hypefocus on one value and hold it up as the key to the church. This will cause the church to decline and die.
The mission is the foundation of what drives the church, over the long haul. The values and the vision work to support the vision, but they are not more important than the vision. The role of the leader is to help the church remain focused on the mission to which God is calling them. This will require attention to the values and the sharing of a vision. Still the mission must be the thing which all other aspects comeback to. The mission is what the church is all about and the values and the vision are how the mission will be recognized. What is your focus?