The awesome power of “informal missionaries”.
We cannot hesitate to believe that the great mission of Christianity [in the First Three Centuries] was in reality accomplished by means of informal missionaries.
Adolf Harnack, The Mission and Expansion of Christianity, 1902
The chief agents in the expansion of Christianity appear not to have been those who made it a profession or a major part of their occupation, but men and women who earned their livelihood in some purely secular manner and spoke of their faith to those whom they met in this natural fashion.
Kenneth Scott Latourette, A History of the Expansion of Christianity
The view that witnessing is “every Christian’s job” was certainly the belief of the early Christians. Their acceptance of this task was perhaps the single most important factor in the astounding outreach and expansion of the early church. It was not simply that Peter, Paul, Stephen, and others spread the good news of salvation in Christ. It was rather that all Christians—small and great, rich and poor, slaves and freedmen—made it their consuming passion to tell others about the Lord.
David J. MacLeod, The Witness of John the Baptist to the Word
But as early as Acts 8 we find that it is not the apostles but the “amateur” missionaries, the men evicted from Jerusalem as a result of the persecution which followed Stephen’s martyrdom, who took the gospel with them wherever they went. It was they who traveled along the coastal plain to Phoenicia, over the sea to Cyprus, or struck up north to Antioch. They were evangelists, just as much as any apostle was.
It was an unselfconscious effort. They were scattered from their base in Jerusalem and they went everywhere spreading the good news which had brought joy, release and a new life to themselves. This must often have not been formal preaching, but the informal chattering to friends and chance acquaintances, in homes. . . on walks, and around market stalls. They went everywhere gossiping the gospel; they did it naturally, enthusiastically, and with the conviction of those who are not paid to say that sort of thing. Consequently, they were taken seriously, and the movement spread, notably among the lower classes.
Michael Green, Evangelism in the Early Church
Witnessing is the whole work of the whole church for the whole age. A light that does not shine, a spring that does not flow, a germ that does not grow, is no more of an anomaly than a life in Christ which does not witness to Christ.
A. T. Pierson
In the beginning the Church was a missionary society: it added to its numbers mainly by the life and speech of its members attracting to it those who were outside.
Roland Allen, The Ministry of the Spirit