I am doing some work on Acts at the moment. I like what Joel Green says below about discipleship.
“The interdependence of the Gospel of Luke and Acts is perhaps nowhere more evident than in the Lukan perspective on discipleship.” (p 22)
“Economic Koinonia… giving is a function not of obligations and debt but of mutuality, generosity, solidarity and need. Economic koinonia would thus grow out of, as well as symbolize, kinship.” (p 22)
“What Jesus had called for in his Sermon on the Plain (Lk 6:27-38, esp. Lk 6:35)—dispositions of kinship giving rise to practices of material generosity—the early church is reported to practice (Acts 2:44-45; 4:32—5:11; see also Acts 6:1-6; 11:27-30)… [Luke] outlines a disposition of kingship and generosity, an orientation toward the needs of others and toward the generosity of God that characterizes the Christian community outside the normal constraints of reciprocity and the gift-obligation cycle. Accordingly Barnabas is introduced as an exemplary figure who embodied the ideal of kinship that was to characterize the whole community (Acts 4:32, 36-37).” (p 22)
“Witness and Allegiance. One of the hallmarks of Luke’s narrative is the consistency with which faithful witnesses attract opposition and with which opposition leads to the spread of the gospel.” (p 22)
“Faithfulness calls for a fundamental allegiance to Jesus as Lord, which for a basic social and political stance within the [Roman] empire (Cassidy), and this may well generate opposition. Peter, John, Stephen and Paul may thus serve as models for Christians who in the course of the church’s mission face similar struggles.” (pp 22-23)
Source: Joel B Green, “Acts of the Apostles” in Dictionary of the Later New Testament and its Development, edited by Ralph Martin and Peter Davids (Downers Grove: IVP, 1997).