This research combines historical, religious, and Law and Economics analyses to investigate the institution of betrothal (known as "engagement" in contemporary contexts) under the Law of Moses. Our analyses indicate that Mosaic betrothal provides a mechanism for allocating risk, managing transaction costs, and designing incentives. Additionally, formal microeconomic and game-theoretic models were employed to compare legal regimes that require formal dissolution with those that permit low-cost separation. The findings show that Mosaic betrothal functions as a multistage commitment device that progressively increases exit costs. This theoretically deters opportunism, encourages premarital investment, and stabilizes match formation. However, marriage market equilibria are sensitive to relative costs, incentives, and risks. These findings complicate the conventional interpretation of Mosaic law as either purely oppressive or purely protective. Instead, Mosaic betrothal emerges as a dual institution. It materially reproduces gendered inequality through asymmetric obligations, yet simultaneously mitigates its most destabilizing effects through legal safeguards, reputational constraints, and enforced commitment. In this framework, religion functions not only as a cultural or political superstructure, but also as a mechanism for embedding and stabilizing economically efficient, yet normatively ambivalent, arrangements of inequality. Beyond its economic logic, the study explores how legal structures influence religious identity, gender inequality, and social cohesion. Betrothal emerges as a covenantal and contractual institution that embeds religious norms within enforceable legal forms. By bringing Law and Economics into the study of Mosaic law, this research aims to promote interdisciplinary dialogue in religious studies by offering a new analytical perspective on how ancient religious institutions regulated inequality, structured commitment, and mediated social order.