Millennial Day Theory

The Millennial day theory, or the Sabbath millennium theory, is a theory in Christian eschatology in which the Second Coming of Christ will occur 6,000 years after the creation of mankind, followed by 1,000 years of peace and harmony. It is a very popular belief accepted by certain premillennialists who usually promote young earth creationism.

The view takes the stance that each millennium is actually a day according to God (as found in Psalm 90:4 and 2 Peter 3:8), and that eventually at the end of the 6,000 years since the creation, Jesus will return. It teaches that the 7th millennium is actually called the Sabbath Millennium, in which Jesus will ultimately set up his perfect kingdom and allow his followers to rest. The Sabbath Millennium is believed to be synonymous with the Millennial Reign of Christ that is found in Revelation 20:1-6.

Early premillennialists included Pseudo-Barnabas,Papias,Methodius, Lactantius,CommodianusTheophilus, Tertullian,Melito,Hippolytus of Rome, Victorinus of Pettau and various Gnostics groups and the Montanists. Many of these theologians and others in the early church expressed their belief in premillennialism through their acceptance of this sexta-septamillennial tradition. This belief claims that human history will continue for 6,000 years and then will enjoy Sabbath for 1,000 years (the millennial kingdom), thus all of human history will have a total of 7,000 years prior to the new creation. Christians throughout history have often considered that some thousand-year Sabbath, expected to begin six thousand years after Creation, might be identical with the millennium described in the Book of Revelation. This view was also popular among 19th- and 20th-century dispensational premillennialists. The term "Sabbatism" or "Sabbatizing" (Greek Sabbatismos), which generically means any literal or spiritual Sabbath-keeping, has also been taken in Hebrews 4:9 to have special reference to this definition.

...
Wikipedia