In his book The Story of Christianity: The Early Church to the Dawn of the Reformation, Gonzalez says, “It is clear that the enormous spread of the Gospel in those first few centuries was not due to the full-time missionaries, but rather to the many Christians who traveled for other reasons—slaves, merchants, exiles condemned to work in the mines, and the like” (1984, p. 99). But only 85 pages earlier, Gonzalez writes, “The political unity wrought by the Roman Empire allowed the early Christians to travel without having to fear bandits or local wars” (p. 14). In Paul’s day (as we find in the book of Acts), Paul and his companions were able to travel from city to city sharing the gospel. They could freely preach in the open and the only people they had to fear were their fellow Jews or the trinket merchants of other religious systems. It was not the government that gave Paul grief, but the religious types, trying to protect their religious ways.
However, a couple centuries later, the great persecutions seem to have removed the ability for “professional” missionaries and church planters to work as they did. The persecution brought the Great Commission right into the lives of everyday believers. The very thing trying to stop the growth of the Church was also the thing that birthed an evangelical flame within the individuals of the body. Now, taking out one person had very little impact upon the mission to move the gospel to the darker places, as the traders, slaves, soldiers, and exiles did.
And if I may, I would like to look at the present through a lens from history. In nations where Christianity is being greatly persecuted, the gospel still moves. Yes, I believe it is in part due to brave missionaries; however, history might suggest it is through the simple movement of faithful believers, submitting to the direction of the Holy Spirit. If we can learn anything from history, it is that not only do the brave missionaries deserve our support, but also the believers, already in the nation, who can take the gospel where it needs to go. And we should also realize that even in our comfortable little unpersecuted bubbles, we should not rely on the "professional missionaries," the books, tracts, music, TV shows, preachers, etc, we should carry the gospel wherever we go.
González, Justo L. The story of Christianity: The early Church to the dawn of the Reformation. Vol 1. San Francisco: Harper & Row, 1984.