The Amman Message (AM) has been celebrated as a landmark declaration for Islamic reform and intra-Muslim unity. It affirms the legitimacy of diverse Islamic schools of thought, denounces sectarian violence, and reasserts Islam's ethical contributions to global civilization. While often studied as a theological or political statement, this paper examines the deeper legal and discursive mechanisms at work, with attention to the strategic redeployment of classical Islamic legal concepts, most notably ijmāʿ(consensus). Rather than reproducing medieval doctrine, the AM selectively reinterprets ijmāʿ to stabilize orthodoxy, foster solidarity across Muslim communities, and reframe Islam's global engagement. In this context, Islamic law emerges not simply as a fixed system of rules but as a flexible, unifying discourse capable of addressing both internal fragmentation and external portrayals of Islam as inherently divisive. By tracing how juristic consensus is invoked within the AM and its related initiatives, the paper argues that the AM simultaneously revives and reshapes classical categories in the service of pluralism, interreligious diplomacy, and political legitimacy. The analysis proceeds in four stages. First, it outlines the AM's aims and doctrinal foundations. Second, it situates the concept of ijmāʿ within classical Islamic jurisprudence and highlights how the AM reframes it, drawing on the insights of scholars such as Mohammad Kamali and Wael Hallaq. Third, it considers the implications of this framework, with the AM positioned as a precursor to broader Muslim-Christian initiatives. Finally, the paper situates these developments in their political context, showing how reinterpreted legal categories function as tools for interfaith diplomacy, normative reconstruction, and Muslim engagement with global ethics. In so doing, it contributes to broader debates on the evolution of Islamic law as a medium for identity, legitimacy, and civilizational dialogue.