“Why should we give money to go overseas when we have needs right here in our own communities?” I have heard this statement and others like it from good, faithful church members. These people are well-meaning and sincere, but have a wrong perception of what missions is about.
Acts 1:8 said that the early church were to be witnesses of Christ in Jerusalem, in all Judaea, Samaria, and unto the uttermost part of the earth.  A simple breakdown of this verse helps give understanding to why we give money to send men to countries that we have never been to; to minister to people we have never met, nor will ever meet.
First of all Jesus said they were to be witnesses of him “both in Jerusalem, and in all Judaea…” The word “both” means that while they are ministering in Jerusalem, they are at the same time to be reaching out to all Judaea. While they are starting churches in Judaea, they are at the same time to be working in Samaria. You get the point. We as the church are responsible to reach not only the area in which we live, but also the world. Which brings me to my second point…
Jesus said that they were to be witnesses for him “unto the uttermost part of the earth.” We are called to the world, not just to our little neck of the woods.