Why does a marriage take place? In most modern societies, it is because both man and woman agree to live as husband and wife, at least prior to the US supreme court decision which now grants as a matter of right under the American constitution for same sex couples to marry just as the heterosexual couples do. In essense, there must be agreement and consent from two parties to give it a most solemn effort to be together for life if it is at all possible. What about a pastor and a church?
In most churches, it is because the pastor and the church through its leaderhip agree and consent for the pastor to be accepted as pastor and for the pastor to accept the church's call to be its pastor. If it is possible, as if by divine appointment, it should be a long term commitment on both sides. Perhaps not as solemn as a marriage that lasts forever as even the best of pastor-congregation relationships sometimes end in a break-up in the bond of the pastor and the church for one reason or another. Even marriages end up in divorce, so there is no surprise for short term pastorate because sometimes things just don't work out. In the initial months, six months to a year at the most, both sides should know whether the pastor's appointment will be an enduring one. For how can both walk together unless the two agree, says the prophet Amos? Horses and donkeys can't run together. The pastor needs a team of leaders that shares his vision just as the church needs its pastor to understand its aspirations, fears and hopes. Unless both sides come to an agreement and conflict is minimized, then it is almost impossible the pastor to stay long, however much he loves the congregation.