Timekeeping in ancient Israel.

The calendar most of the planet uses, called either the western calendar or the Gregorian calendar, originated in 1582 when Pope Gregory 13 introduced it as an update of the Roman calendar adopted by Julius Caesar in 45BC. Since Gregory introduced it right after the Protestant split, it took a while before all Protestant countries adopted it. Various Orthodox churches still haven’t adopted it, preferring to stick with Caesar’s calendar, ’cause it’s not Catholic. Meanwhile nations which aren’t even predominantly Christian—’cause of western influences or trade—do use it. As well as their own local calendars. Japan, fr’instance.

Israel likewise uses the western calendar. And its local calendar, the one which predates the western calendar by centuries: The Hebrew calendar.

That’s the calendar we find in the bible. It’s what we call a lunisolar calendar: It’s lunar, in that months start on the new moon. But it’s adjusted to sync up with solar years, so that the year always begins in spring, round the time of the vernal equinox, and doesn’t drift too far away from it.

The Hebrew calendar actually predates the Hebrews. It was used all over the ancient middle east, including by the Assyrians and Babylonians who conquered Israel. The Hebrew calendar’s months all have Assyrian names—although a few of the original Canaanite names slipped into the bible:

1. אָבִיב/Avív (“green”), the first month. Ex 12.2, 13.4 Tel Aviv (KJV “Telabib”) in Babylon Ek 3.15 was named for it; Tel Aviv in Israel is named for that.
2. זִֽו/Ziv (“bright”), the second month. 1Ki 6.1
7. אֵיתָניִם/Eytaním (“strong ones”), the seventh month. 1Ki 8.2
8. בּוּל/Bul (“produce”), the eighth month. 1Ki 6.38

Otherwise the scriptures simply called the months “third month,” “fifth month,” and so forth. (Like September/seventh month, October/eighth month, and so on… and yeah they aren’t the seventh and eighth month, but blame Gregory for that.) We don’t know what the ancient Canaanite names were. No doubt many months were named for pagan gods, just like the Roman calendar, so the Hebrews didn’t care to use or record them.

In any event here are the current names.

MONTH	DAYS	WHEN	BIBLE HOLIDAYS
ניִסָן Nisán	30	Spring: Mid-March to mid-April	Passover
אִיָּר Iyyár	29	Mid-spring: Mid-April to mid-May
סִיוָן Siván	30	Late spring: Mid-May to mid-June	Shavuót (Pentecost)
תַּמּוּז Tammúz	29	Summer: Mid-June to mid-July
אָב Av	30	Mid-summer: Mid-July to mid-August
אֱלוּל Elúl	29	Late summer: Mid-August to mid-September
תִּשׁרִי Tišreí	30	Fall: Mid-September to mid-October	Yom Kippur, Sukkot
מַרְחֶשְׁוָן Markhéšvan	29/30	Mid-fall: Mid-October to mid-November
כִּסְלֵו Khislév	29/30	Late fall: Mid-November to mid-December	Hanukkah
טֵבֶת Tevét	29	Winter: Mid-December to mid-January
שְׁבָט Ševát	30	Mid-winter: Mid-January to mid-February
אֲדָר Adár	29/30	Late winter: Mid-February to mid-March	Purim

Multiple new years.

When the LORD instructed Moses and Aaron how to observe Passover, he told ’em from now on, the month they did it, he considers their first month:

Exodus 12.1-2 KJV

1 And the LORD spake unto Moses and Aaron in the land of Egypt, saying, 2 This month shall be unto you the beginning of months: it shall be the first month of the year to you.

Thing is, on 1 Tišreí there’s a holiday called רֹאשׁ הַשָּׁנָה/Roš haŠaná, “head of the year,” usually rendered “Rosh Hashanah.” And that’s the Jewish New Year. Which confuses all the Christians who’ve read Exodus 12: How’s it the Jewish New Year when the LORD designated Nisán as the beginning of the year?

Tišreí was the original first month, before the LORD changed it. Jews consider it “the beginning of the secular year,” and since everybody but religious leaders consider the secular year the real year… yeah, Rosh Hashanah is the real new year. It’s when they update the year they put on the calendars, from 5781 to 5782 to 5783 and so on.

1 Nisán is considered the beginning of the religious year. Thing is, Rosh Hashanah is totally a religious holiday. It’s not called Rosh Hashanah in the bible, but the LORD nonetheless told the Hebrews to make it a holiday, and treat it as a Sabbath.

Leviticus 23.23-25 KJV

23 And the LORD spake unto Moses, saying, 24 Speak unto the children of Israel, saying, In the seventh month, in the first day of the month, shall ye have a sabbath, a memorial of blowing of trumpets, an holy convocation. 25 Ye shall do no servile work therein: but ye shall offer an offering made by fire unto the LORD.

Ten days later it’s Yom Kippur, and Jewish custom is to fast for those 10 days. (Although some of ’em tend to “fast” like Evangelicals, and just go without meat or bread or coffee or something.) These 10 days are the High Holy Days, or High Holidays, and they’re a big, big deal to religious Jews. So the LORD’s designated new year? Meh.

The number of each year, back in bible times, was determined by how long the current king had ruled. Or how long the neighboring king had ruled.

1 Kings 22.41 KJV

And Jehoshaphat the son of Asa began to reign over Judah in the fourth year of Ahab king of Israel.

The first year of Jehoshaphat of Jerusalem, was the fourth year of Ahab of Samaria. And the first year of Ahab’s son Ahaziah of Samaria, was the 17th year of Jehoshaphat. And the first year of Ahab’s other son, Jehoram of Samaria, was the 18th year of Jehoshaphat. And the first year of Jehoshaphat’s son, Jehoram of Jerusalem, was the fifth year of Jehoram of Samaria. Yep, two Jehorams at once. That’ll confuse you… as will the wonky system of figuring the year by the king. It’s not practical at all when you’re trying to determine events which happened centuries ago. You gotta know how long ago, and precisely how long, the two Jehorams ruled.

And we actually don’t. The bible doesn’t bother with fine details like that, because even though it’s full of history, it’s not about history; it’s about God. Scholars have tried adding up all the reigns, much like they’ve tried adding up the ages in genealogies, but you still won’t get exact dates that way. It doesn’t take into account kings whose reigns overlap, or the fact the bible regularly rounds the numbers. We figure these guys reigned in the 800s BC, but if you want exact years… well, one reference book is gonna suggest one timetable for the kings, and another reference book is gonna suggest another.

We honestly don’t have any dates pinpointed till the bible starts mentioning Babylonian kings. ’Cause the Babylonians practiced astronomy, and they knew how to pinpoint dates.

So where’d the current numbering of Hebrew years come from? Medieval rabbis. They estimated God created the universe on 1 Tišrei 3761 BC, and have been counting up since then. (Yep, even sooner than the 4004 BCE which young-earth creationists prefer; go figure.) So this means today is the in the Hebrew calendar, according to Hebcal.com.

New moons and blood moons.

The Hebrew months are lunar, which means every month begins on the new moon. That’s why months vary between 29 and 30 days, instead of the western calendar’s 30 and 31 days: It’s synced with the moon.

As a result the Hebrew year comes out to between 354 and 356 days. Which, y’notice, doesn’t quite line up with the earth’s 365¼-day trip round the sun. So what keeps their calendar from sliding around the seasons like the Muslim calendar? Simple: A lunisolar calendar includes a leap month. If the year ends and it’s not yet spring, they add a month. The leap month is called Adár Aléf/“Adár A,” or Adár Rishón/“First Adár.” Followed, of course, by the usual Adár—which is called Adár Bet/“Adár B,” or Adár Šení/“Second Adár.”

Since lunar eclipses only happen on new moons, various “prophecy scholars” try to make a big deal about how various “blood moons” coincide with significant Jewish holidays—like Rosh Hashanah. Which just goes to show how ignorant they are of how the Hebrew calendar works: Of course blood moons coincide with Jewish holidays. It’s a lunar calendar! But like Jesus said, these things don’t mean the End has come. Only that some “prophecy scholar” is trying to peddle books to the fearful.

The ancients used to celebrate new moons, so the Hebrews did too. 2Ch 2.4 They tried to make them sacred by offering sacrifices to the LORD, although he didn’t actually command ’em to do so. (He did order a sacrifice every month, Nu 28.14 but it’s debatable whether this sacrifice was required on the first day of the month.) But neither did the LORD forbid new-moon celebrations—so long that the Hebrews actually followed him. When they didn’t, he objected to the hypocrisy of such celebrations. Is 1.13-14 Don’t just make a big display at festivals; worship him for real.

Hebrew days.

The Hebrew days of the week don’t have names, unlike our Sunday, Monday, etc. There’s “first day,” “second day,” and so on. (Nowadays they’ll sometimes go with “Day A,” “Day B,” etc.) Though in New Testament times, Friday became known as “Preparation,” Mk 15.42 because it was the day you finished your work before Sabbath. Mark also called it “pre-Sabbath” (Greek προσάββατον/prosávvaton), though I’m not sure how widely used that term was, since the other gospels went with Preparation. Arguably “Preparation” was what they called any day before a holiday, but since Sabbath was a weekly holiday, when you said Preparation you meant Friday.

I wrote about Sabbath elsewhere. It’s a weekly holiday, and treated more like a holiday than westerners tend to treat their weekends.

Western days begin at midnight, but middle eastern days began at sunset. So when the sun went down on Friday, it wasn’t Friday night; it was Sabbath. Friday night was last night. I know; it’s a tricky thing for some westerners to wrap their brains around. (Though some of us are up past midnight and already know what it’s like to be awake when the day changes: “Well, earlier today… oh, I mean yesterday; it’s after midnight, isn’t it?”)
Hours in the Roman Empire adjusted with the length of the day. Wikipedia Some rabbis offered rulings about when precisely the day changed, like how many stars you can see in the sky after the sun goes down. But most folks followed the usual rule of thumb: The sun’s down; it’s tomorrow.

Hours worked a little differently. Hours were based on the length of time between sunrise, noon, and sunset. There were six hours before noon, and six hours after noon. But as you know, the length of a day in June is a bit different from the length of a day in December. So the hours stretched or shrank to fit. The Hebrews didn’t divide the night into hours, but אַשְׁמֻר֑וֹת/ašmurót, “watches”—named for a night guard’s shifts. The ancient Hebrews had three watches, but by New Testament times they’d added a fourth. These watches naturally shifted in length, same as the hours of the day.

I could chart it for you, but remember: If the day’s any longer or shorter (and it usually is), it’s not gonna precisely line up with western time. These are rough estimates. Really rough.

BIBLICAL TIME	LENGTH	WESTERN TIME (IF SUNSET IS 6PM)
First watch	For three hours after sundown OT days: For four hours after sundown	6pm to 9pm OT days: 6pm to 10pm
Second watch	The three hours before midnight OT days: Four hours in the middle of the night	9pm to 12am OT days: 10pm to 2am
Third watch	The three hours after midnight OT days: For four hours before dawn	12am to 3am OT days: 2am to 6am
Fourth watch	The three hours before dawn OT days: Didn’t have a fourth watch	3am to 6am
First hour	First sixth of the morning	6am to 7am
Second hour	Second sixth of the morning	7am to 8am
Third hour	Third sixth of the morning	8am to 9am
Fourth hour	Fourth sixth of the morning	9am to 10am
Fifth hour	Fifth sixth of the morning	10am to 11am
Sixth hour	Last sixth of the morning, before noon	11am to 12pm
Seventh hour	First sixth after noon	12pm to 1pm
Eighth hour	Second sixth of the afternoon	1pm to 2pm
Ninth hour	Third sixth of the afternoon	2pm to 3pm
Tenth hour	Fourth sixth of the afternoon	3pm to 4pm
Eleventh hour	Fifth sixth of the afternoon	4pm to 5pm
Twelfth hour	Last sixth of the afternoon, before sundown	5pm to 6pm

And since the hours were so flexible, nobody talked in terms of “5:30” or anything like that. Western time wasn’t sorted out for several centuries yet. When the writers of the bible say “it was the sixth hour” or something like that, it was around the sixth hour; they weren’t gonna be as exact as westerners expect. (Just naming the hour at all was pretty darned exact for them.)