In all four New Testament gospels, as we have seen, Jesus sends his followers out to heal. However, only the Gospel of Luke has a direct sequel - the Acts of the Apostles - that shows them doing so. But there are numerous other Christian sources, beginning with the letters of Paul and continuing on into the Middle Ages, that constitute indirect sequels to Jesus’ healings in the New Testament gospels - responses, as it were, to the charge given to his earliest followers. These various sources make clear that early Christians viewed his healings as set forth in the gospels not as once-for-all manifestations of God's power and life, but as something continuing, and to be continued. In the ancient Mediterranean world where, as we observed in chapter 1, life was precarious and good health highly prized, persons offering healing would be welcomed by many.

In his book Christianizing the Roman Empire (1984), Yale University historian Ramsay MacMullen contends that it was in fact Christian miracles, including healings, more than any other factor that won converts. Especially crucial, according to early Christian testimony, was the expulsion of demons, or as moderns might be inclined to say, the healing of mental illness, which in ancient paganism ranked much lower on the healing scale than did bodily ailments. For Jesus’ followers, however, the driving out of demons was a dramatic demonstration of the superiority of the Christian God over the demons and deities of paganism. Various early Christian writers tout it as a distinctive mark of Christianity and as a means of winning converts. Thus, around the middle of the second century CE Justin Martyr boasts that Christians cast out demons by reciting a little credo about Jesus’ crucifixion (2 Apology 6.6; similarly, Justin's Dialogue with Trypho 30.3; 76.7; 85.2-3) - an interesting early example of how the story of the powerless healer begins to be used as a power for healing in his name. A few decades later, Irenaeus, bishop of Lyons, reports that those from whom demons have been expelled are frequently won to Christ [Against Heresies 2.33.4). Tertullian, a couple of decades further still (197 CE), asserts that evil spirits inhabiting humans or masquerading as deities reveal their true identities when a follower of Christ orders them to speak [Apol 23.4).