The Paradise Lost to Paradise Regained book had an extensive discussion of the process of creation from Genesis 1, and was filled with statements like "49,000 years ago, God did such and such," or "It was 29,000 years ago when such and such appeared on the earth," and so forth -- with such seeming precision.
I tried to find the book on the WT CD and interestingly it is omitted -- their books only go back to 1970 even those the WT and Awake magazines go back to 1950....
The 49,000-year concept is last stated in the January 1, 1987 Awake!:
*** w87 1/1 p. 30 Questions From Readers ***In ancient Israel a cycle of 49 years was followed by a Jubilee year (50th year). Does that Jubilee correspond to the period following God?s creative week of 49,000 years?
Because the number 49 occurs in both cases, it might seem that the Jubilee would foreshadow the time following the end of a creative week of 49,000 years. But for mankind in general who receive God?s approval, what occurred during Israel?s Jubilee corresponds more with what will occur during the Millennium, the last thousand years of such creative week, not what follows after that week. Consider the basis for this:
First, the Mosaic Law required that every seventh year be a sabbath for the land; crops were not to be sown, cultivated, or harvested. After the seventh Sabbath year (the 49th year), there came a special Jubilee year, the 50th year. It was a sabbath during which the land was again to rest. More importantly, liberty was proclaimed. Hebrews who had sold themselves into slavery were freed from indebtedness and servitude. Also, hereditary land was returned to families who had been forced to sell it. So the Jubilee was a time of release and restoration for the Israelites.?Leviticus 25:1-46.
Second, a study of the fulfillment of Bible prophecy and of our location in the stream of time strongly indicate that each of the creative days (Genesis, chapter 1) is 7,000 years long. It is understood that Christ?s reign of a thousand years will bring to a close God?s 7,000-year ?rest day,? the last ?day? of the creative week. (Revelation 20:6; Genesis 2:2, 3) Based on this reasoning, the entire creative week would be 49,000 years long.
Noting the similarity in numbers, some have compared the 49 years of the ancient Jubilee cycle to such 49,000 years of the creative week. Reasoning this way, they have thought that Israel?s Jubilee (50th) year should prefigure, or foreshadow, what will come after the end of the creative week.
However, bear in mind that the Jubilee was particularly a year of release and restoration for people. The creative week largely relates to the planet Earth and its development. But with regard to the outworking of God?s purpose for man on earth, the globe itself has not been sold into slavery and thus is not in need of liberation. It is mankind that needs that, and humans have existed, not for 49,000 years, but for about 6,000 years. The Bible shows that some time after Adam and Eve were created, they rebelled against God, thus coming into captivity to sin, imperfection, and death. According to Romans 8:20, 21, Jehovah God purposes to liberate believing mankind from this slavery. As a result, true worshipers on earth "will be set free from enslavement to corruption and have the glorious freedom of the children of God."?See also Romans 6:23.
While the small group selected to be taken to heaven have had their sins forgiven from Pentecost 33 C.E. onward and thus already enjoy the Jubilee, the Scriptures show that the liberation for believing mankind will occur during Christ?s Millennial Reign. That will be when he applies to mankind the benefits of his ransom sacrifice. By the end of the Millennium, mankind will have been raised to human perfection, completely free from inherited sin and death. Having thus brought to an end the last enemy (death passed on from Adam), Christ will hand the Kingdom back to his Father at the end of the 49,000-year creative week.?1 Corinthians 15:24-26.
Consequently, for believing mankind with earthly prospects, the liberation and restoration that marked the Jubilee year in ancient Israel will find a fitting parallel during the coming Millennial Sabbath. Then liberation and restoration will be experienced. That will be under Christ?s rulership, "for Lord of the sabbath is what the Son of man is."?Matthew 12:8.