Troubleshooter

The calendar the Lord established for Israel was a Lunar calendar...
...the Lord said to Moses...

"This month shall be unto you the beginning of months: it shall be the first month of the year to you." Exodus 12:2

...and followed this with specific days set according to the month (literally 'moonth') cycle...

“In the tenth day of this month they shall take to them every man a lamb" Exodus 12:3...

..."...keep it up until the fourteenth day of the same month:" Exodus 12:6...

The 'weekly' Sabbaths were be set to occur according to the same calendar reckoning...
...and the pattern of weekly Sabbaths on day 8, 15, 22, 29 can be demonstrated...
...for the first three months of the Exodus from Egypt...
...a coincidence that can not happen using a Julian/Gregorian calendar.

The Julian calendar was a solar calendar and was not introduced until 46 BC by Julius Caesar...
...so why would the Lord have given Moses a weekly Sabbath reckoning by that method 1400 years earlier?


The weekly Sabbath introduced just prior to leaving Egypt...
...as an echo of the creation and the promise of New Creation...
...to be reenacted each New Moon...
...and was as much a part of the prophetic description of what would happen to Jesus...
...as the killing of lambs, goats and red bulls...
...the Sabbath was a shadow of the rest that we have in Jesus through the Gospel...
...and met its antitype in the doing, dying and rising of Jesus.


This mode of calculating weekly Sabbaths changed as secular calendar calculations were periodically altered...
...to reflect commercial, national and later global interests...
...and religious interests in time standardized their systems to suit...
...but this is not how the Lord established it for Israel's salvation history...
...or how it was still kept by Second Temple Jews when Jesus dwelt among us.

There is historical evidence that the lunar determination of weeks...
...was still being used by some until about 250 AD.

The Lord even predicted that the Sabbath would be forgotten...

Lamentations 2:6 "And he hath violently taken away his tabernacle, as if it were of a garden: he hath destroyed his places of the assembly: the LORD hath caused the solemn feasts and sabbaths to be forgotten in Zion, and hath despised in the indignation of his anger the king and the priest."