While we rightly honor and support those who take the Gospel to foreign countries, missionaries are essentially doing in another place what every believer is to do in the location they are. Perhaps not in the sense of a vocational ministry, but in obeying two imperatives: The Great Command and the Great Commission.
Missions is simply the church being the church somewhere else.
The Great Commission is the task of world-wide disciple-making, beginning with the proclamation of the Gospel and resulting in mature, individual Christ-followers.
The Great Command is to “love the LORD your God.” This love is the heart of obedience to the Great Commission. It is impossible to fulfill the one while living in disobedience to the other.
You can have all the training, all the preparation, all the experience, all the tools for sharing the Gospel, but if you do not preserve what is most important – Love for God – you will not obey the Great Commission.