Luke alone recorded that Jesus gave the Twelve both power (Gr. dynamis, spiritual ability) and authority (Gr. exousia, the right to exercise power). The parallel Gospel accounts refer only to authority. In both his Gospel and in Acts , Luke stressed the validation of gospel preaching with signs and wonders. Other false teachers could do powerful miracles, presumably by Satan"s power (cf. Acts 13:6-10; Acts 19:13). Consequently it was necessary that Jesus" disciples could validate their preaching with powerful miracles as Jesus did. The Twelve received authority over all demons. None would prove too powerful for them. The disciples" primary duty was to preach the kingdom of God, and their way of showing the Jews that God was behind their preaching was by performing miracles. Thus they followed Jesus" precedent (cf. Luke 8:26-56; Luke 9:11). They, as Hebrews , were to demonstrate concern for people"s souls, but also their bodies. [source][source][source]