Why the Explosion of the Early Church?

While exact statistics about the early Christian movement before the time of Constantine cannot be known, we can be sure of the rapid growth of the church in this era of history.  In The History of Christian Missions, Stephen Neill writes,

we may say that by the end of the third century there was no area in the Roman Empire which had not been penetrated to some extent by the Gospel. (pg 35)

Starting as a movement of Jews in Palestine, by 311 the gospel spread throughout the Hellenistic-Roman culture and even as far as India to varying degrees. How did this rapid expansion of the gospel happen?

Neil argues seven factors contributed to the early Christian movement: (pg 35-37)

• a burning conviction that a “great event had burst upon them in creative power. They knew the that the world had been redeemed, and they could not keep to themselves tidings of such incomparable significance for the whole human race.” The gospel spread rapidly through the little conversations and actions of people in the cities of the Roman Empire as well as the full-time ministries of itinerant ministers.
• they addressed the most basic questions of the human experience with a conviction of certainty that the mystery religions, empire cults, and Greek philosophies could not bring.
• many early Christians lived noble lives in the midst of the corruption and seductive temptations of the Empire
• they shared a common life with people of different classes, ethnicities, and cultures in a society that divided people into “greek” or “barbarian,” “slave or free”
• they cared for each other, practiced hospitality, and cared for the poor and outsiders deep

The Emperor Julian writes in early fourth century:

Atheism [the Christian Faith] has been specially advanced through the loving service rendered to strangers, and through their care for the burial of the dead. It is a scandal that there is not a single Jew who is a beggar, and that the godless Galilaeans care not only for their own poor but for ours as well; while those who belong to us look in vain for the help that we should render them

• persecution and meeting in secret- created an interest in knowing why they defied the authority of and were willing to face terrible persecution by the Empire

For a more in depth analysis of the early Christian movement, Alan Hirsch has written well on the subject in his book: The Forgotten Ways