In the early twentieth century, with the rise of the Nazi state in Germany and, consequently, the onset of world wars led by Adolf Hitler, new challenges emerged for the church. Reactions to these events and the ensuing situation varied, resulting in two starkly opposing factions within the Protestant church: the Confessing Church resisting the regime and the German Christians supporting it. As government actions and clergy friendly to the regime intensified, members of the Confessing Church, led by Karl Barth, convened to prevent the German Christians’ portrayal of Christology and the Christian church from being distorted, and they approved the Barmin Declaration in six articles. This study, employing historical analysis, examines the background and consequences of issuing this declaration. The findings show that the declaration aimed to confront the notion of dual authority and to assert Christ’s lordship over the church and the state, thereby blocking the Nazi regime’s expansionist aims. Although the declaration left a notable mark and somewhat challenged the intellectual foundations of the ruling spectrum, it did not exert a dramatic influence on attitudes due to insufficient uptake by Confessing Church members.