Stephan Witetschek, «Sankt Paul in Ketten. Zur Paulus-Ikonographie in der Apostelgeschichte und im Corpus Paulinum.», Vol. 96 (2015) 245-272
Chains or bonds are a standard feature of representations of Paul in early Christianity. In the narrative of Acts 21–28 they appear to be an element of literary iconography employed by 'Luke the painter'. This iconography begins with Paul himself, who interpreted his bonds as worn 'in Christ' (Phil 1,13) and himself as 'prisoner of Christ Jesus' (Phlm 1.9). The Deutero-Pauline Epistles follow suit: In Colossians and Ephesians the bonds appear as the iconographical attribute, while in 2 Timothy they are perceived and tackled as a problem. In any event, Paul is remembered as the Apostle in fetters.