If we now assume that Luke is the author of the Acts, the question remains as to the character of the sources used by him. One is at liberty to appeal to Lu 1:1-4 for the general method of the author. He used both oral and written sources. In the Acts the matter is somewhat simplified by the fact that Luke was the companion of Paul for a considerable part of the narrative (the "we" sections, Ac 16:11-17; 20:5; 21:18; 27:1-44 and Ac 28:1-31). It is more than probable that Luke was with Paul also during his last stay in Jerusalem and during the imprisonment at Caesarea. There is no reason to think that Luke suddenly left Paul in Jerusalem and returned to Caesarea only when he started to Rome (Ac 27:1). The absence of "we" is natural here, since it is not a narrative of travel, but a sketch of Paul's arrest and series of defenses. The very abundance of material here, as in Ac 20:1-38 and Ac 21:1-40, argues for the presence of Luke. But at any rate Luke has access to Paul himself for information concerning this period, as was true of the second, from Ac 13:1-52 to the end of the book. Luke was either present or he could have learned from Paul the facts used. He may have kept a travel diary, which was drawn upon when necessary. Luke could have taken notes of Paul's addresses in Jerusalem (Ac 22:1-30) and Caesarea (Ac 24:1-27 through Ac 26:1-32). From these, with Paul's help, he probably composed the account of Paul's conversion (Ac 9:1-30). If, as I think is true, the book was written during Paul's first Roman imprisonment, Luke had the benefit of appeal to Paul at all points. But, if so, he was thoroughly independent in style and assimilated his materials like a true historian. Paul (and also Philip for part of it) was a witness to the events about Stephen in Ac 6:8 through Ac 8:1 and a participant of the work in Antioch (Ac 11:19-30). Philip, the host of Paul's company (Ac 21:8) on the last journey to Jerusalem, was probably in Caesarea still during Paul's confinement there. He could have told Luke the events in Ac 6:1-7 and Ac 8:4-40. In Caesarea also the story of Peter's work may have been derived, possibly even from Cornelius himself (Ac 9:32 through Ac 11:18). Whether Luke ever went to Antioch or not we do not know (Codex Bezae has "we" in Ac 11:28), though he may have had access to the Antiochian traditions. But he did go to Jerusalem. However, the narrative in Ac 12:1-25 probably rests on the authority of John Mark (Ac 12:12,25), in whose mother's house the disciples were assembled. Luke was apparently thrown with Mark in Rome (Col 4:10), if not before. For Ac 1:1-26 through 5 the matter does not at first seem so clear, but these chapters are not necessarily discredited on that account. It is remarkable, as ancient historians made so little mention of their sources, that we can connect Luke in the Acts with so many probable fountains of evidence. Barnabas (Ac 4:36) was able to tell much about the origin of the work in Jerusalem. So could Mnason. Philip also was one of the seven (Ac 6:5; 21:8). We do not know that Luke met Peter in Rome, though that is possible. But during the stay in Jerusalem and Caesarea (two years) Luke had abundant opportunity to learn the narrative of the great events told in Ac 1:1-26 through Ac 5:1-42. He perhaps used both oral and written sources for this section. One cannot, of course, prove by linguistic or historical arguments the precise nature of Luke's sources in Acts. Only in broad outlines the probable materials may be sketched.
Continued in ACTS OF THE APOSTLES, 8-12.