The third great Priestly covenant was mediated by Moses and marks the last defining moment in the Priestly history of the divine-human bond. This covenant, made with the people of Israel, was regulated by an extensive set of laws and regulations in the books of Exodus, Leviticus, Numbers, and Deuteronomy. The people express their solidarity with God in this covenant by observing the Sabbath day, called in Exodus 31:12-18 the "sign of the covenant," and by keeping the other laws.