Hi Magnum,
It is my understanding that the WTS starts its "70 Years" [of desolations] at the same moment that it starts its "2,520 Years" [of Gentile Rule]. These are the periods I meant and I apologise for my imprecision.
The question in my mind concerned the Society's starting event of that period: (1) When Jerusalem was destroyed [but that was in the 5th month]; (2) When Gedaliah was murdered; (3) When the Jews started on their trek to Egypt; (4) When Zedekiah was captured; (5) When Jews left the soil of Judah [ostensibly leaving the land depopulated.
The following is all I was able to readily locate.
Doug
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The lowly people that King Nebuchadnezzar left behind in the
land of Judah had a governor appointed by him over them, namely, Gedaliah.
However, he was killed in the seventh month (Tishri), and then the remaining
Jews fled down to Egypt out of fear of Babylon, but only to have the hand of
the king of Babylon reach them down there later on. In this way the land was
left desolate in the seventh month, without man or beast, as Jeremiah had
foretold. (Babylon the Great Has Fallen!, pages 166-167)
Jehovah's purpose to have Jerusalem and the land of Judah
emptied, desolated of both man and domestic animal. (Babylon the Great Has
Fallen!, page 121)
The beginning of the
seventy years of Judah's desolation had yet eleven years to wait (Ezekiel
1:1-3) They began after the last king, Zedekiah the uncle of Jehoiachin, was
dethroned and when the land of Judah was left
desolate. (Babylon the Great Has Fallen!, page 138)
“The cities of Judah I shall make a desolate waste without
an inhabitant."—Jeremiah 34:8-22. (Babylon the Great Has Fallen!, page
153)
By the flight of the faithless, disobedient Jews down to
Egypt the land of Judah was left desolate, without human inhabitant and
domestic animals. This proved Jehovah's prophecy by Jeremiah true. It occurred toward
the middle of the seventh month, Tishri or Ethanim (September-October), which
would be near October 1, 607 B.C. (Babylon the Great Has Fallen!, page 163)
Like the forty-ninth year of the cycle of sabbaths, the
Jubilee year was to be a sabbath year for the God-given land, and so a Jubilee
sabbath of the land began in the seventh month, Tishri. (Leviticus 25:8-22)
During that month, as the fearful Jews needlessly fled down to Egypt and left
the land of Judah utterly desolate and without human inhabitant, a place to be
shunned by passersby, the land must have heaved a sigh of relief, as it were.
Now it began to enjoy an uninterrupted run of sabbath years in compensation for
all the Sabbath years that the disobedient Israelites had failed to keep. How
many years of sabbath rest was the land to enjoy? Figuratively, a perfect
number of years—seventy. (2 Chronicles 36:17-23; compare also Daniel 9:1, 2).
(Babylon the Great Has Fallen!, pages 163-164)
Those Gentile Times, those "appointed times of the
nations," would end 2,520 years from near the middle of the seventh lunar
month (Tishri) of 607 B.C. (Babylon the Great Has Fallen!, page 180)
Jeremiah chapter 52 describes the momentous events of the
siege of Jerusalem, the Babylonian breakthrough, and the capture of King
Zedekiah in 607 B.C.E. Then, as verse 12 states, “in the fifth month, on the
tenth day,” that is, the tenth day of Ab (corresponding to parts of July and
August), the Babylonians
burned the temple and the city. However, this was not yet the starting point of
the “seventy years.” Some vestige of Jewish sovereignty still remained
in the person of Gedaliah, whom the king of Babylon had appointed as governor
of the remaining Jewish settlements. “In the seventh month,” Gedaliah and some
others were assassinated, so that the remaining Jews fled in fear to Egypt. Then only, from about October 1,
607 B.C.E., was the land in the complete sense “lying desolated … to
fulfill seventy years.”—2 Ki. 25:22-26; 2 Chron. 36:20, 21. (All Scripture is
Inspired of God and Beneficial, page 285)
The 70 years were to be a period when the land of Judah and
Jerusalem would enjoy “sabbath rests.” This meant that the land would not be
cultivated—there would be no sowing of seed or pruning of vineyards. (Leviticus
25:1-5, NIV) … When did the land of Judah become desolated and unworked? … When did the 70 years commence? Certainly
not following the first time that Nebuchadnezzar laid siege to Jerusalem. Why
not? Although at that time Nebuchadnezzar took many captives from Jerusalem to
Babylon, he left others behind in the land. …
[The Babylonians] razed the city, including its sacred
temple, and they took many of its inhabitants captive to Babylon. Within two
months, “all the people [who had been left behind in the land (added by the
WTS)] from the least to the greatest, together with the army officers, fled to
Egypt for fear of the Babylonians.” (2 Kings 25:25, 26, NIV) Only then,
in the seventh Jewish month, Tishri (September/October), of that year could it
be said that the land, now desolate and
unworked, began to enjoy its
Sabbath rest. To the Jewish refugees in Egypt, God said through Jeremiah: “You
have seen all the disaster that I brought upon Jerusalem and upon all the
cities of Judah. Behold, this day they are a
desolation, and no one dwells in them.” (Jeremiah 44:1, 2, English Standard
Version) So this event evidently
marked the starting point of the 70 years. (The Watchtower, October 1,
2011, pages 27-28)
Jehovah allowed the Babylonians to conquer his people,
destroy Jerusalem and its temple, remove Zedekiah from “the throne of the
kingship of Jehovah” and take the Jews into Babylonian exile. Events that
followed “in the seventh month” led the few Jews who had remained in the land
to flee to Egypt, so that Judah then lay completely desolate. (Kingdom Comes,
page 136)
Historians calculate that Babylon fell in early October of
the year 539 B.C.E. (Kingdom Comes, page 136)
October, 537 B.C.E., which date therefore marks the
completion of the foretold 70 years of desolation. That historical information
is important to us in determining the beginning of “the appointed times of the
nations.” Since the 70 years of desolation for Judah and Jerusalem ended in 537
B.C.E., they began in 607 B.C.E. That would be the year when Zedekiah ceased to sit upon the “throne of the kingship of Jehovah”
in Jerusalem. It therefore marks also the date for the beginning of the Gentile Times. (Kingdom Comes, page 136)
The prophet Jeremiah predicted that the Babylonians would
destroy Jerusalem and make the city and land a desolation. (Jeremiah
25:8, 9) He added: “And all this land must become a devastated place, an
object of astonishment, and these nations will have to serve the king of
Babylon seventy years.” (Jeremiah 25:11) The 70 years expired when Cyrus the
Great, in his first year, released the Jews and they returned to their
homeland. (2 Chronicles 36:17-23) We believe that the most direct reading
of Jeremiah 25:11 and other texts is that the 70 years would date from when the Babylonians destroyed Jerusalem and
left the land of Judah desolate.—Jeremiah 52:12-15, 24-27; 36:29-31.
(Kingdom Comes, pages 187-188)
The land of Judah was to keep a “sabbath, to fulfill seventy
years.” (2 Chronicles 36:21) How? By lying as a “desolate waste without man and domestic animal”. … Those seventy years of utter desolation of
the land of Judah and Jerusalem without
man and domestic animal. (Paradise Restored, page 132)
The seventy years of unbroken captivity to Babylon did not
begin until 607 B.C.E., in the month Ethanim, when the land was left completely desolate when its remaining
inhabitants went down to Egypt. Then
the Jews as a nation went into exile at Babylon, without a king at
Jerusalem. This exile was for an uninterrupted period of seventy years.
(The Watchtower, December 1, 1964, page 735)