Of particular interest are the ‘we’ passages in Acts. (Ac 16:10-17; 20:5-15; 21:1-18; 27:1-28:16) It is natural to assume that Luke, as author of the book, is including himself within this designation.
‘If Luke is accepted as the companion of Paul, then the “we” passages of Acts disclose that Luke was in Philippi (possibly his hometown), and that there he joined Paul. (Ac 16:10-17 ) Then he later rejoined Paul when the latter returned to Philippi. (Ac 20:5-15 ) Luke then journeyed with Paul on his way to Jerusalem and stayed with Philip at Caesarea. (Ac 21:1-18 ) Then, after Paul’s two-year imprisonment in Caesarea, Luke sailed with him to Rome.’ (Ac 27:1-28:16 ) (WWCH)