12 GIANCARLO BIGUZZI dental that Jerusalem and Rome are the two geographical poles of the journey of the Gospel narrated in Acts. 5. The significance of the number two in the work of witnessing Pairs of characters in every possible combination are numerous both in the Lukan Gospel and in Acts. This phenomenon was first noticed by H.J. Cadbury 20, and since then commentators have of- fered various interpretations. According to C.H. Talbert and A.C. Clark, Luke arranged his protagonists in pairs reflecting the aesthetical sensibility of his period. In the literature of the Greek- Roman world the technique of synkrisis, or comparison, is frequent and is a genre used for instance by Plutarch in his Parallel Lives 21. The encomia made use of synkrisis, praising the virtues of a cele- brated personage by comparing or contrasting him with another famous person, still living or from the past. R.C. Tannehill and D. Marguerat, authors sensitive to the unity of literary works, argue instead for a redactional-narrative explanation. Luke links together the episodes, both within Acts and between the two volumes of his double work, in many ways. For example, he brings on to the scene the same character a second or third time, or pro- tagonists who echo each other because of their similarity, such as the two centurions of the Gospel (Luke 7,2.6; 23,47) and the two H.J. CADBURY, The Making of Luke-Acts (London 1958) 233-235. Cf. 20 also A.C. CLARK, “The Role of the Apostles”, Witness to the Gospel. The Theology of Acts (eds. H. MARSHALL – D. PETERSON) (Cambridge – Grand Rapids, MI 1998) 185: “Luke has a fondness for pairs”. Cf. A.A. TRITES, The New Testament Concept of Witness, (SNTS. MS; Cambridge 1997) 134, who writes : “Frequently in Acts the witnesses and preachers of the Christian faith are referred to in pairs”, and then lists the case of Peter and John, Barnabas and Paul, Paul and Barnabas, Judas and Silas, Barnabas and Mark, Paul and Silas, Silas and Timothy. CLARK, “The Role of the Apostles”, 185: “This concern for balance 21 extends to parallels between characters. The aesthetic and literary context is im- portant in this connection. Above all, it is helpful to relate this phenomenon to the ubiquity of a particular rhetorical technique in the ancient world, synkrisis (comparison). Instruction in this technique form part of the progymnasmata, the preliminary exercises in rhetorical education. The technique was widely used in encomia and other forms of biography, though it was not confined to this genre ”. Clark adds finally: “The most famous use of this technique is, of course, in Plutarch’s Parallel lives”.