This essay offers an analysis John Witte, Jr.’s contribution to the study of the relationship between Christianity and law as an autonomous branch within the broad field of law and religion. The author discusses Witte as a Christian jurist educated in Reformed Protestantism and influenced by Abraham Kuyper and Harold J. Berman, among others, and describes and evaluates the interdisciplinary, interdenominational, and international project on Christianity and law headed by Witte, to which more than five hundred scholars (jurists, theologians, philosophers, historians, and sociologists) are contributing. Witte analyzes the interaction between Christianity and law from a relational, biographical, and jurisprudential perspective, and underlying his project is the idea that the relationship between Christianity and law is not merely accidental, but has a metahistorical significance and an enduring value for the development of humanity. Although the project has already borne much fruit, there is room for further maturity and methodological purity as it is still in its early stages.