A persistent theological divide between Judaism and Christianity rests upon misconceptions about Jewish religious life during the intertestamental period. While social relations between the two faiths have markedly improved, especially in the United States, traditional Christian narratives continue to portray this era as one of Jewish spiritual decline—a view that distorts both religions' understanding of their shared heritage. Through qualitative analysis of scholarly works, biblical and rabbinic literature, and historical sources from both Jewish and Christian perspectives, this research reveals instead a period of remarkable Jewish religious innovation. The centuries following the Babylonian return witnessed the canonization of Scripture, establishment of synagogue worship, elimination of idolatry, and flourishing of oral law traditions. These findings demonstrate that Christianity emerged not from Judaism's margins but from its vibrant center, fundamentally challenging traditional supersessionist theology. This historical reality demands a reconceptualization of Jewish-Christian theological relationships, suggesting that both religions carry distinct but equally valid divine mandates. Moving forward requires grounding interfaith dialogue in accurate historical understanding rather than inherited prejudices.