This paper examines the Zionist national mission to mobilise Jewish ethnic communities in Arab countries, in the period preceding the establishment of the state of Israel. It draws on archival texts to trace a phenomenon known in Jewish historiography as 'Shadarut'; a voluntary religious practice of fundraising which was widespread in the Jewish world for hundreds of years. The paper shows how this prenational religious practice (to be labelled 'the cloak') was adopted and incorporated into the Zionist national project ('the cage'), first generating tension between the Jewish religious establishment and the Zionist 'secular' movement, and then blurring the distinction between Judaism as a religion and Judaism as a national identity. The paper shows how secular emissaries of European origin arrived in Arab countries as religious emissaries ('shadarim') and aspired to discover a strong religious fervour among members of the Jewish communities there. This is because in the eyes of the Zionist (ostensibly secular) movement, being religious Jews in Islamic countries was a criterion that demarcated them from their Arab neighbours. This analysis entails two main conclusions: (a) that contrary to the experience of the European Zionist national movement in which secularism and the revolt against the Jewish religion played a central role, in Islamic countries it was particularly the Jewish religion, and not secular nationalism that was used to mobilise the Jewish community into the Jewish national movement; (b) that the 'shadarut' practice refuses to yield to the epistemological imperatives and the common divisions that arise from the binary distinction between 'religiousness' and 'secularity', particularly in the Middle East. Some implications for contemporary Israeli society are discussed.