The storyline in this chapter details how interpretations of Mosaic Law were ultimately central to the far-reaching legal and moral transformation from limited-term servitude to lifelong, racialized Black African slavery in early America. The Massachusetts Body of Liberties (1641) enshrined slavery as a legal institution based on Mosaic legal categories of lawful capture and purchase while influential theologians like the Dutch Calvanist Godfried Udemans and the Puritan Cotton Mather utilized portions of Exodus, Leviticus, and the Ten Commandments to formulate an apologetic for ‘Christian slavery’ and catechize the enslaved into obedience. Simultaneously, the period saw the emergence of Mosaic-based condemnations of slavery. Early Puritan and Quaker dissenters like Richard Saltonstall, William Southeby and George Fox invoked the prohibition against man-stealing in Exodus 21 and the principle of sabbatical release in Deuteronomy 15 to challenge the moral legitimacy of perpetual bondage, establishing foundational arguments for later abolitionism. By the time of the 1700–1701 Sewall-Saffin exchange, Samuel Sewall’s anti-slavery appeal to Mosaic Law (and the broader Bible) clashed with John Saffin’s enduring defense of perpetual slavery rooted in Leviticus 25 and related passages to help elucidate and establish the repertoire of pro- and anti-slavery arguments and related Mosaic passages which would remain at the heart of the debate across the ensuing centuries, re-appropriated and at times re-interpreted in ever-transforming and intensifying historical contexts.