On the Seventy Sevens Prophecy of Daniel (9:24-27); and in particular, what length of a year is likely being alluded to?

Between the 69th week and the 70th week is an undetermined period of time known as the church age. It's referred to as a 'mystery' in the NT. I believe the 70th week is the great tribulation.

7 x 7 = 49 7 x 62 = 434 49 + 434 = 483 483 years x the 360-day lunar year = 173,880 days

173,880 days / the 365.24 day solar year = 476 years in our calendar system

The months would all be 30 days.

The prophecy says seventy sevens (seventy weeks) are cut off from the 2300 year prophecy and apply to the Jewish nation. The 62 weeks plus the seven weeks make up one part (483 years) of the prophecy and ends with the baptism of Jesus (start of His ministry).

It then is followed by the last week which, as the prophecy makes clear, is split in half (Dan. 9:27). Jesus ministered for 3½ years to the Jews (confirming the covenant) and then was crucified.

After His crucifixion He sends His disciples to the Jews for another 3½ years and then at the stoning of Stephen the last week of Dan. 9's prophecy is over when the disciples are sent to the Gentiles.

Here is an article that covers the starting point of the prophecy as well as other aspects: When Did the Seventy Weeks of Daniel 9:24 Begin?

Dan 12:11-12, which I quote below, provides the basis for inferring the calendar system used in the book of Daniel.

“From the time that the regular sacrifice is abolished and the abomination of desolation is set up, there will be 1,290 days. How blessed is he who keeps waiting and attains to the 1,335 days!” (Dan 12:11-12)

Clearly "the time that the regular sacrifice is abolished" in Dan 12:11 refers to "the middle of the week" when "sacrifice and grain offering" will be "put a stop" in Dan 9:27, within the prophecy of the 70 weeks previously revealed to Daniel by the angel Gabriel:

“And he will make a firm covenant with the many for one week, but in the middle of the week he will put a stop to sacrifice and grain offering; and on the wing of abominations will come one who makes desolate, even until a complete destruction, one that is decreed, is poured out on the one who makes desolate.” (Dan 9:27)

There is one calendar system in which, if the first half of a week of years is reckoned to have lasted 1260 days, the second half of that week of years can last from 1,290 to 1,335 days, and it consists of 30-days months in which an additional month is added every 6 years and a further additional half-month is added every 60 years, so that the average year length is 365.25 days.

This calendar system was never actually used, but was only a theoretical construct [1] devised either by the Jewish Priestly (P) authorial school or by a Babylonian astronomer ca. 450 BC at P's request for the purpose of its use in the biblical text.

The construction of this calendar by Babylonian astronomers ca. 450 BC is wholly plausible because by that time they had already reckoned that the length of the solar year was between 365.25 and 365.24 days [2].

Choosing the first value, since 365.25 is 6,5;15 in sexagesimal notation, it is immediately evident for anyone using a base-60 numerical system that achieving an average year length of 6,5;15 days requires adding 15 additional days every 60 years. Thus, a 60-year intercalation cycle comprises:

• 50 regular 360-day years, totalling 18000 days,
• 9 leap 390-day years, totalling 3510 days, and
• 1 extra-leap 405-day year (the 60th)

for a total of 21915 days and average year length = 21915 / 60 = 365.25 days.

Now, since the intercalation cycle runs since Creation, unless you know the absolute number of a particular year since Creation, i.e. its AM value, you cannot know whether that year is regular, leap or extra-leap, because you do not know its position in the intercalation cycle. Therefore, if you reckon the middle of a "week of years" on the basis of 3.5 regular years, i.e. on the basis of the first half of that "week of years" comprising 1260 days, there are 4 possible values for the number of days till the end of that "week of years", depending on the respective week's case:

• 6 regular + 1 leap: 6 · 360 + 390 = 2550 = 1260 + 1290 (Probability 3/4)

• 6 reg + 1 extra-leap: 6 · 360 + 405 = 2565 = 1260 + 1305 (Probability 1/12)

• 5 regular + 2 leap: 5 · 360 + 2 · 390 = 2580 = 1260 + 1320 (Probability 2/15)

• 5 reg + 1 leap + 1 extra-leap: 5 · 360 + 390 + 405 = 2595 = 1260 + 1335 (Probability 1/30)

Therefore, a priori there is a 75 % probability that the time from the middle of the week of years in question - reckoned by counting 1260 days from the week's beginning - to the end of that week will be 1290 days, but there is a 3.33 % probability that it will be 1335 days. (The calculation of the probability of each case is in https://www.academia.edu/44143168/ .)

To sum up, on the basis of Dan 12:11-12 we can infer that the book of Daniel assumes a calendar system with average year length of 365.25 days.

Notes

[1] It was based on the 360-day calendar comprised of 12 30-day months that was used in Mesopotamia for administrative purposes since the early dynastic time ca. 2600 BC until Ur III times ca. 2100 BC and then was used in the training of scribes in an unbroken tradition until it appeared in astronomical tables in the astronomical compendium MUL.APIN, composed sometime before 700 BC, as an "ideal" year, and whose use as an "ideal" year for astronomical purposes is documented until ca. 300 BC. Source:

Brack-Bernsen, Lis, “The 360-Day Year in Mesopotamia”, in Steele, John M. (ed.) Calendars and Years: Astronomy and Time in the Ancient Near East, Oxbow Books, 2007, pp. 83-100.

[2] The 19-year cycle of leap-year intercalations at fixed intervals in the lunisolar calendar was implemented in year 10 of the reign of Xerxes I (486–465 BC), i.e in 476/5 BC, implying that Babylonian astronomy had already discovered the "metonic" cycle by then.

Ossendrijver, Mathieu, “Babylonian Scholarship and the Calendar During the Reign of Xerxes”, in: C. Waerzeggers & M. Seire (eds.), Xerxes and Babylonia: The Cuneiform Evidence (Louvain [etc]: Peeters, 2018 [= Orientalia Lovaniensia Analecta, nr. 277]), pp. 135-163.

To your question, “what length of a year is likely being alluded to?” There have been three proposals.

• First, was the early church historian, Africanus, who used a lunar year (354 days)

• Secondly, there are several count systems using solar years. (365.25 days)

• Thirdly, there is Sir Robert Anderson’s ‘prophetic’ year. (360 days)

It needs to be understood that the Jewish calendar is actually a ‘luni-solar’ calendar which is given a 13th month every three years approximately. Therefore, any count of Daniel’s seventy weeks will average out to our solar cycle. Moreover, the ‘weeks’ were synonymous with the ancient Hebrew Sabbatical cycle.

I believe that the terminus a quo was 457 BC (Artaxerxes 7th year) and the terminus a quem was 34 AD. Jesus was crucified in the midst of the 70th week, 30 AD.

Timeline below.

The year being alluded to is the solar year of 365.24219 days.

It is 490 solar years to the exact day from 8th April 458 BC (Julian), the date being referred to in Ezra 7:9 and the date of the Resurrection on 5th April AD 33 (Julian). The Gregorian dates for both these events was 3rd April. So the Resurrection was exactly 490 solar years after the event of Ezra 7:9. On 8th April 458 BC Ezra and the Jews with him began their journey back to Jerusalem to have the city restored to Jewish control, and to rebuild the city walls. There is no decree at all in the book of Nehemiah.. it doesn't exist. The decree being put into effect in Nehemiah is the one Ezra obeyed in 458 BC.

The fudge of 360 days ("prophetic" days in a year) of Anderson doesn't even work "to the exact day" which was Anderson's claim. (Neither does it work for Hoehner's amended dates.)

See the following linked answer: What arguments are there against the 69 week periods of Anderson and Hoehner?

The Seventh Day Adventist claim that the decree in Ezra chapter 7 was in 457 BC is not correct, in fact they seem to contradict themselves in the article referred to by a previous answer. In the article https://www.adventistbiblicalresearch.org/materials/when-did-the-seventy-weeks-of-daniel-924-begin/ and in the section under "Chronology, regnal years of Artaxerxes, section A5 - "Babylonian Historical sources" it is stated about the historical records:-

They do, however, abundantly confirm the previously established pattern which indicates that 465 B.C. was the twenty-first year of Xerxes and that Artaxerxes I’s first full regnal year began on Nisanu 1 in the spring of 464 B.C.

Quite so! Therefore Nisanu 1 of of the 7th year of Artaxerxes I (Ezra 7:7-9) was 458 BC, not 457 BC, which is exactly the claim of Richard A. Parker and Dubberstein in their standard work "Babylonian Chronology - 626 BC to AD 75".

Though, contra the SDA article, Xerxes I was killed between 14th Abu and 18th Abu of 465 BC. The 1st Abu was on 22nd July so this equates to sometime between the 4th and the 8th August... "the day number is imperfectly preserved and all numbers between 14th and 18th [of Abu] are possible" - Professor Abraham J. Sachs (Parker & Dubberstein, page 17).

Those scholars who assert Xerxes was killed later in the year (of 465) rely on the historical data from Egypt, such as Manetho's record. But it is better to take the historical data from Babylon itself which was right on top of the scene of the crime. The data is much more likely to be reliable.

I appreciate the time that others took to post responses to my questions. Since then, I have considered the question more deeply and would like to put forth the following argument as a basis for a likely conclusion:

It is quite clear that the prophecy is not referring to 70 weeks (of days). Furthermore, based on the thoughts that Daniel was thinking at the time the Angel arrived---a natural assumption would then be to declare that the prophecy refers to seventy weeks (of actual years), which I guess, many have done, including myself.

However, one notices in Rev. 11:2-3 (Douay-Rheims) --- "[2] But exclude the outer court of the temple; do not measure it, for it has been handed over to the Gentiles, who will trample the holy city for forty-two months. [3] I will commission my two witnesses to prophesy for those twelve hundred and sixty days, wearing sackcloth." that 42 months is equivalent to 1260 days.; the conclusion being that ONE MONTH EQUALS 30 DAYS.

Moreover, when we read a little further on in Daniel beyond Chap. 9; specifically, Dan. 12:7 --- "And I heard the man that was clothed in linen, that stood upon the waters of the river: when he had lifted up his right hand, and his left hand to heaven, and had sworn, by him that liveth for ever, that it should be unto a time, and times, and half a time.... "

This phrase, "unto a time, and times, and half a time" is used earlier as well, in Dan. 7:25 --- "And he shall speak words against the High One, and shall crush the saints of the most High: and he shall think himself able to change times and laws, and they shall be delivered into his hand until a times, and times, and half a time.

But also, we find it again in Rev. 12:14 --- "And there were given to the woman two wings of a great eagle, that she might fly into the desert unto her place, where she is nourished for a time and times, and half a time, from the face of the serpent." WHICH IS CONNECTED WITH VERSE 6: "And the woman fled into the wilderness, where she had a place prepared by God, that there they should feed her a thousand two hundred sixty days."

Given the earlier conclusion that a Month = 30 Days--- the necessary conclusion is that "A TIME, AND TIMES, AND HALF A TIME" = 1260 Days = 42 Months.

If I were writing an article, or a chapter in a book, I would likely try to further develop this argument; however, in the interest of brevity, let me jump to the conclusion:

If one considers the Hebrew, the Angel does not say in Daniel 9:24, "Seventy weeks" (which is the conclusion of many English biblical translations); nor does he say "Seventy sevens (of 365.25 or so years)", which is the literal conclusion of many; rather, seemingly, he says "Seventy sevens". And so, I suggest that we may perhaps, consider this as "Seventy sevens" of "time"---which, in light of the above, I dare say, suggests Seventy Sevens (of 360 day periods of time).

Other books in Scripture also make reference to periods of time in which one can make analogous arguments and draw similar conclusions; e.g., Esther, and Genesis.