Discussions of the Spirit in Luke-Acts have often centered around the concept of δύναμις and its relationship to πνεῡμα. Graham Twelftree portrays his view of this relationship in his most recent, In the Name of Jesus, when discussing the nature of Christian exorcism and spiritual warfare. Although he doesn't really bring anything new to the table on the specific relationship of these two concepts, it is interesting how he strings some thoughts together regarding Luke-Acts.
In regards to Luke 5:17 and 8:46 Twefltree makes the statement, ". . .δύναμις works immediately and impersonally, responding to the contact of any believing person without the knowledge or approval of Jesus" (137). But (and here he moves forward in 'filling-out' this notion), "It is the powerful presence of God's Spirit received for healing through faith" (137). What Twelftree seems to be saying here is that δύναμις is the outworking of the presence of God's πνεῡμα. This means, for Luke, that the source of healing is attributed directly to the immediate presence of the Spirit rather than through any incantation or human personality.
While there is definitely more to be said on this idea, what I want to focus on here is how he moves this into the healing and exorcism ministry of the early church. He states, "From Luke's perspective, early Christian exorcism was successful because the exorcists brought Jesus into the situation either by using his name or issuing a command as if passed down from him" (148, emphasis is mine). This is an interesting concept which I think has fallen away in the modern church culture. As people quite obsessed with our own power and influence, we like the concept of δύναμις, regardless of its specific relationship to the Spirit.
Yet, it is quite interesting to note that Luke's picture of δύναμις is predicated on a specific relationship with πνεῡμα - meaning, power comes from a right relationship with the Spirit and not just our desire to have power. Twelftree's statement refers to the belief among the early Christians that as they invoked the name of Jesus they were introducing the presence of Jesus into the situation. And this was reserved for the advancement of the kingdom, especially in exorcism, healing and spiritual warfare. (It is doubtful that parking spaces and vending machine selection warranted such an invocation among the first believers.)
Rather than using 'the name of Jesus' as a way to cap off an otherwise self-centered and egotistic string of wants, the tradition preserved in the Gospel is that the spiritual presence of Jesus held the power of the coming kingdom which was going to overcome the powers of the world. Therefore, going in the name of Jesus requires the church to go in the full power of the Spirit and the dedication of making the kingdom a reality within the world. Sadly, this is missing in large part among modern Christians.
"Exorcism was not simply healing a sick person but the bringing of salvation" (148).