This question gets asked often. Perhaps you have thought of it yourself. A preacher preaches, a shepherd shepherds, an evangelist evangelizes and deacons serve. A missionary missions? What is it that they are off doing besides tourism? Paul answers this for us in his letter to the Thessalonians.
From First Thessalonians chapter two we can see three things that a missionary should do. They should speak the gospel of God (1 Thess. 2:1-6). This should be obvious. What is not so obvious to some is how it should be done. It should be done with boldness even amid great opposition (2:2). The exhortation should be from the pure gospel (2:3). It should not be done with flattering speech or greed (2:4-5). Nor should it be done to receive glory from men with whom they work or those that would know about the work (2:6).
They should speak the gospel of God with gentle exhortation (1 Thess. 2:7-12). Paul specifically mentions with the gentleness of a nursing mother and the exhortation as a father with his children (2:7, 11). He said they sought to be gentle, devout, blameless and upright among them (2:10). Paul said that they had a fondness for the believers that they would have laid down their own lives for them. Likewise, a missionary should live a sacrificial life among those with whom he works (2:8). They should know you love them without a word. With that love and concern, the missionary should exhort those around him on how to walk in God’s kingdom (2:12). Realizing always that this is God’s work, not the missionary’s work.
They should speak the gospel of God with gentle exhortation to imitate the churches of Judea (1 Thess. 2:13-16). Missionaries should be in constant prayer that the people who are receiving the message should do so as if it were the word of God that works in their hearts (2:13). As a missionary, you teach people to imitate the church of Judea (2:14). Missionaries shouldn’t be teaching the church of the Bible Belt. They should look to the church of the first century as the example in all things. A missionary should help people understand that hardship will be a part of the life of a child of God (2:15-16). This life is not heaven. We look forward to a rest. In this life we labor so that we might receive that rest. All who strive to live godly lives in this life will suffer. This is not a pessimistic outlook on life, just a realization that we are at war with one that does not want the church to succeed.
As you think about what a missionary does, you might be thinking, “I can do that.” You would be right. We all have a way that we can take part in this work. God has made it possible for us to be more than ready to do His work in this world.