This detailed study of the Sabbath comes at a time when there is so much confusion and debate among both Jewish and Gentile believers regarding what the Bible really teaches about it. The apologetics used for mandatory Sabbath-keeping are almost exclusively based upon the Old Testament for obvious reasons: there is no New Testament command for believers in general or Jewish believers in particular to keep the Sabbath. The purpose of this study, then, will be to examine what the Sabbath is in both testaments. At the same time, it will examine arguments used to support mandatory Sabbath-keeping. This study examines the Sabbath in Judaism, the Old and New Testaments, the issue of Sunday worship and the Sabbath, the Sabbatical Year, and the Year of Jubilee.