Studies about the origin of monotheism—the belief in one god while denying the existence of all others, have continued to be a matter of debate among Hebrew Bible scholars. The debate has often fallen into two contrasting categories. On the one hand, there are those who argue for an early origin in which it is posited that monotheism must have begun somewhere between the time of Moses and the monarchical period. On the other hand, others have argued for a late date which stretches from the exilic period to the Persian period. In spite of the different explanations given by the proponents of early monotheism, this thesis builds on the hypothesis that exclusive monotheism was only realized during the Persian period. The monotheistic rhetoric that characterized the message of Deutero-Isaiah, only came to be put into practice by the confessional community of faith among the returning exiles in Yehud.