MEMORIAL VS PASSOVER

[Manuel Boyet Enicola]

How was Passover determined during Jesus' days? They don't have sophisticated astronomical equipment then. That should be the key, I suppose....

[JW Insider]

13 hours ago, Manuel Boyet Enicola said:

How was Passover determined during Jesus' days? They don't have sophisticated astronomical equipment then. That should be the key, I suppose....

It's a very good question. I'll try to give the longest answer I can think of.

The simplest answer is that they watched the phases of the moon. We don't watch the moon all that closely these days, but it made for a very good calendar because every full moon to the next full moon was 29.5 days apart. So if you just started the month when the moon was "empty" and waited for that first tiny sliver of moon after that, you would call that the new month, or new moon. That was the first day of the month, and they knew that the month was going to have either 29 or 30 days, and they would typically have to alternate it, because the actual length was 29.5. So if the previous month was given 29 days, then the next month would have 30, and vice versa.

The full moon happens 14.75 days after the "empty" new moon (which is half of 29.5). So, on average the 15th day of the month was a full moon.

Passover was designated for the 14th or 15th of the month called Nisan, the first month of "springtime."

So the simplest answer is that they waited for the first full moon after the new moon (new month) called Nisan.

And I'm sure you know it gets a little more complicated than that. Here's why:

A LITTLE PROBLEM

They didn't actually start the new month exactly when the moon became "empty" but started it when they saw that first sliver. Well, sometimes you can't always see that first sliver on the first day, even when it's there. That's because the moon might still look completely "empty" around sunset, andbut it's hard to see, it's a difficult time to look for that first sliver, due to the typical position of the moon around sunset when there is still a lot of brightness from the sun outshining that tiny sliver. That's not too serious, however, because that sliver will definitely be there on the very next day, and if the previous month had the maximum number of days, 30, then you don't even have to look to know it's going to be there. Over time, you just learn that you can alternate the days of all twelve months 30,29,30,29,30,29,30,29,30,29,30,29 and you will be almost perfect so that every new year starts out with a 30 day month (Nisan) and ends with a 29 day month (Adar). Depending on exactly when you started counting that "new moon" sliver, you could be 24 to 36 hours past the astronomical new moon, and therefore could see a full moon anywhere from 13 to 14 days after the sliver is seen, or 14 to 15 days after the potential earliest calling of the first day of the month where a new moon was assumed. In any case, if you were off by a day one month, you'd be forced to be back on track the next month, by rotating the 29 or 30 day months, or by physically sighting the new moon phase.

A BIGGER PROBLEM

So the lunar calendar is hardly ever more than one day off just by keeping it in sync with the phases of the moon. But if you multiply 29.5 average days times 12 months you only get 354 days, and we know that a solar year is 365.25 days. 12 lunar months was 10+ days shy of a solar year.

And the seasons will only work from a solar calendar, not a lunar calendar. And they planted by the seasons, so by the time the last winter month of Adar came around, they would see some good winter rains, moisture in the air, even some extra water in the streams fed from the higher grounds and mountainous regions to the north. So they would have already planted when the temperature and moisture conditions were best, and they almost always reap a barley harvest by the middle of the first spring month of Nisan.

People in Biblical times planted by a solar calendar. If they didn't, they would start planting 10 days earlier every year, and pretty soon their crops would not get enough moisture and do terribly. By the time three years rolled around they would be an entire 30+ days (an extra month) early, and the crops would not grow correctly. In 6 years, they would be about two lunar months behind.

Make no mistake, they would notice the difference in the efficiency of the crops right away:

• (Exodus 9:31, 32) 31 Now the flax and the barley had been struck down, because the barley was in the ear and the flax had flower buds. 32 But the wheat and the spelt had not been struck down, because they were later crops.
• (Ruth 1:22) . . .They came to Bethʹle·hem at the beginning of the barley harvest.
• (Ruth 2:23) 23 So she stayed close to the young women of Boʹaz and gleaned until the barley harvest and the wheat harvest came to an end. And she kept dwelling with her mother-in-law.

At the time it was written, a Jewish person could read Ruth 1:22 through 2:23 and know almost exactly how long Ruth stayed in Bethlehem.

THE SOLUTION

They could come up with a system that added one extra lunar month, a thirteenth month (a "leap" month) every three years. But it turns out that even this wasn't perfect, and over time they would notice. It was really over 11 days off every year or more than 34 days and adding a 29 or 30 day month, would still leave them 4 or 5 days off every three years. Those days would add up, it wouldn't be bad after adding 1 month in 3 years, or even 2 months in 6, but by the time they had added 6 months in 18 years, they'd be nearly a month off again. The solution which works out almost perfectly turns out to be adding, an extra month again. So it's not 6 lunar months every 18 years, but 7 every 19. 

7 every 19 is almost perfect.

19 years of 365.25 days is 6,939.75 days.

19 years of 354 days + 7 more months of 29.5 days is 6,932.5 days.

That was rounding off, it turns out that a "lunation" is not exactly 29.5 days, but about 44+ minutes longer than 29.5 days, or three-fourths of an hour longer, each month. (And, of course, a solar year is not exactly 365.25, either, it's 365.2422.) All considered, it turns out that this extra 3/4 of an hour every month, aligns the 7 extra lunar months even much closer to a perfect 19 solar years.

WHEN DID THEY ADD THE EXTRA MONTHS?

Without a perfect calculator, the 7 additional months every 19 years, would have to be learned over time. 1 month every three years would have been simple, and thus 6 months every 18 would have resulted. It would have been better to throw that 7th extra month somewhere in the middle of the range of 18 or 19 years to keep the average number of days as close to the solar calendar as they could. Also, they wouldn't want to throw in the extra month back to back with a year that just had a leap month because that would obviously just put them an extra number of days off, when the differences could be smoothed out by spacing that 7th month into the mix by moving a couple of the previous 3 year intervals to 2 year intervals (for the leap month).

A specific pattern would invariably develop over time. In truth, however, we don't have the records of exactly in which years the Hebrew calendar added the extra months. But we do know that, by necessity, all lunar calendars added an extra month, on average, exactly 7 times every 19 years. We have evidence from stone tablets of the nations around them to know that they were doing the same thing, and we can get a better idea of the practice of how they smoothed out those 7 extra months as evenly as possible over the 19 year cycles.

It turns out, that there is a very likely explanation for how it was done in those other nations who kept a larger number of dated chronicles. (Or at least where a larger number have survived.) 

Even without precision astronomical instruments, it turns out to be pretty easy to figure out the exact solstices of the solar year. From this information, and in other ways too, you can also figure out, very nearly, the exact equinoxes, too. In Israel, as with almost anywhere on earth (within a wide range of latitudes), you can just watch where the sun comes up relative to your eastern-facing windows of your house, or the place where it's shadow is cast from that window to a wall on the other side. Let's say a person in the days before artificial light was easy, performed a certain chore and need maximum sun in the morning, or wanted to keep the first rays of morning sun out of their eyes, or wanted a potted plant to get maximum light all year, or wanted a certain glass ornament to shine from the morning sunlight as many days of the year as possible. All of these circumstances, would have resulted in movements of objects, chairs, tables, beds, curtains, etc. Every year those movements would follow the same patterns, and the farthest points of those necessary movements to maximize (or minimize) sunlight resulted in the marking of the solstices, and the midpoints were often the equinoxes. The northernmost or southernmost positions of the sun on the horizon, also exactly marked the solar-calculated seasons every year.

How accurate could those markings be? We can get a hint by reading the book of Enoch. Many copies of the book survive, and it was written as early as 300 B.C. Writers projected astronomical knowledge onto Enoch because of the coincidence that he lived for 365 years. The same number of days in a solar year.

The book of Enoch proposes a calendar that starts out at the idealized 360 days but with an extra day added to one month every quarter, or season, for a total of 364 days a year. Because this was with full knowledge of the need for "leap" days, we can also be sure that "Enoch" understood the need for an adjustment of an extra day or so every couple of years, in addition. Here's a quote:

• "The moon brings on all the years exactly, that their stations may come neither too forwards nor too backwards a single day; but that the years may be changed with correct precision in 364 days. In three years the days are 1,092; . . . To the moon alone belong in three years 1,062 days . . . So that the moon has thirty days less than the sun and stars. . . . The year then becomes truly complete according to the station of the moons and the station of the sun . . ." (Enoch 74:11-17 {73:13-14, 12, 16})

• Enoch 74:2-6 And these serve four days, which are not calculated in the calculation of the year. 3 Respecting them, men greatly err, for these luminaries truly serve, in the dwelling place of the world, one day in the first gate, one in the third gate, one in the fourth gate, and one in the sixth gate.  And the harmony of the world becomes complete every three hundred and sixty-fourth state of it. For the signs,  The seasons,  The years,

Whenever a "leap" day is needed, it is merely not counted in the calculation of the year. This way he keeps his idealized 360 and just keeps adding the leap day every season as needed, to keep the sun's seasons aligned. The main purpose was evidently to keep the "week" more inviolable. His method had the advantage of having exactly 52 weeks in a year, and then probably only needing a "leap" week now and then instead of a leap month.