Many people going into full time Christian service present God with a little list explaining to Him exactly what kind of ministry they will be doing at the various points in their lives. They tell God that they are going to serve as a missionary for three years, and then pastor a parish for five years, then go to grad school and do a research degree in something, etc. They have it all figured out and are "informing God" of the way things are "going to be."
It can be rather comical, then, when we realize that God will have His way with us no matter what we have planned. One might think that he is going to go into a full time teaching ministry, for example, when all of sudden God calls him to go and serve a parish... even if he is scared to death of parish work. Or one might think that she is called to be a homemaker and administrative assistant, when all of a sudden God calls her to the mission field. God will have His way with us no matter what, as the stories of the bible - from Joseph to Saul of Tarsus - teach us.
The point is to always be open to where and how God is calling us to serve. Just because we may not have opportunities in the area of ministry that we have imagined we'd serve in doesn't mean that God cannot or will not use us in some other way. He may intend for us to doing something very different than we've imagined. Just as He called Moses, who had speech impediment or something like that, to be His spokesman before pharoah, so He may be calling each of us to serve Him in some previously unimagined way.
