This dissertation addresses the concept of authoritative testimony in Luke-Acts. Specifically, the dissertation argues that ancient audiences would have understood particular elements in the narrative of Luke-Acts to be instances of the topos of divine testimony, considered by ancient rhetoricians to be the most authoritative form of testimony when seeking to persuade an audience. This argument is made first through an investigation of the term topos/locus in the ancient rhetorical handbooks, an analysis which demonstrates that a possible definition for topos is a source of proofs from which an orator can draw in order to bring evidence in a forensic or deliberative speech. Also from this analysis, one sees that divine testimony is a type of external topos, and is considered authoritative due to the outstanding virtue of the gods. According to the rhetorical handbooks, the gods testify through various means, including utterances (both direct speech and through oracles), other sounds and/or visible emanations from the heavens (such as fire), the presence and flight of birds, portents on the earth, and dreams and visions. A survey of ancient speeches and treatises demonstrates that all of these elements were used in trials to both demonstrate the piety of one's client and to disparage an opponent, in an effort to be rhetorically persuasive. These forms of divine testimony are found in Hellenistic histories and biographies, including narratives from Greco-Roman, Jewish, and early Christian authors. Divine testimony in these works also serves the same function as in speeches and treatises, namely to demonstrate the virtue or piety of the protagonists and the lack of these qualities in the antagonists. This is also the case in Luke-Acts. All of the forms of divine testimony found in the extra-biblical literature are found in Luke-Acts as well, with the exception of divine testimony through the examination of entrails and through oracles. In the case of oracles, this dissertation argues that first-century audiences would have understood references to the OT in Luke-Acts in the same way as references to and citations of oracles in Hellenistic histories and biographies.by James R. McConnell Jr.Ph.D.