I’d like to clarify how the Hebrew calendar actually works, and how it changed over time.
There are weekly Sabbaths, based on 6 day work, one day rest cycle. This is clearly stated in the Bible- even in the Ten Commandments.
In addition, there are rest days when no work is to be done, on the major holidays. These are not related to the weekly Sabbaths. The holidays are celebrated on particular days of the month, which can ‘land’ on different days of the week.
Months start when the New Moon is observed. From Biblical times until about the 4th century AD this was accomplished by having witnesses who had seen the New Moon report to the religious leaders of the time. It was known that the months were 29 or 30 days long, so if the New Moon wasn’t seen on the 30th, then the current month was 30 days long and the next month started the following day- whether or not the New Moon was sighted (this could be a result of cloudy or rainy weather, besides astronomical conditions) . There always was a human element in this, as the calendar depended on human witnesses.
Over time, starting around the 4th century AD, the system of having witnesses report on the New Moon sighting became impractical. Instead, the timing of when the New Moon could theoretically be seen was calculated. This calculation is fairly accurate.
The details of when a new month actually starts are a bit complicated. For example- what if the new moon could be sighted only very late on the 30th day- and witnesses wouldn’t have had time to report it? In addition, sometimes the length of a month is deliberately adjusted in order to ensure that holidays don’t land on particular days of the week.
Besides the above, an additional month is sometimes added to the year, in order to keep the lunar month cycle synchronized with the solar (and agricultural) years. This is a common arrangement- the Chinese calendar works the same way. The Muslim calendar doesn’t have this feature, so Ramadan ‘drifts’ through the seasons.
Chair
There are weekly Sabbaths, based on 6 day work, one day rest cycle. This is clearly stated in the Bible- even in the Ten Commandments.
In addition, there are rest days when no work is to be done, on the major holidays. These are not related to the weekly Sabbaths. The holidays are celebrated on particular days of the month, which can ‘land’ on different days of the week.
Months start when the New Moon is observed. From Biblical times until about the 4th century AD this was accomplished by having witnesses who had seen the New Moon report to the religious leaders of the time. It was known that the months were 29 or 30 days long, so if the New Moon wasn’t seen on the 30th, then the current month was 30 days long and the next month started the following day- whether or not the New Moon was sighted (this could be a result of cloudy or rainy weather, besides astronomical conditions) . There always was a human element in this, as the calendar depended on human witnesses.
Over time, starting around the 4th century AD, the system of having witnesses report on the New Moon sighting became impractical. Instead, the timing of when the New Moon could theoretically be seen was calculated. This calculation is fairly accurate.
The details of when a new month actually starts are a bit complicated. For example- what if the new moon could be sighted only very late on the 30th day- and witnesses wouldn’t have had time to report it? In addition, sometimes the length of a month is deliberately adjusted in order to ensure that holidays don’t land on particular days of the week.
Besides the above, an additional month is sometimes added to the year, in order to keep the lunar month cycle synchronized with the solar (and agricultural) years. This is a common arrangement- the Chinese calendar works the same way. The Muslim calendar doesn’t have this feature, so Ramadan ‘drifts’ through the seasons.
Chair