Practical Focused Talmudic Astrology – Background for Tractate Sabbath 129b

Practical Focused Talmudic Astrology

Background for Tractate Sabbath 129b


Most modern Rabbinic authorities have dismissed the value and acceptability of any astrological contemplation. However, and without delving into the theological or legal ramifications, it is interesting to note that during Talmudic times the Rabbinic authorities were prescribing or warning different acts dependent on the astrological considerations.

In the Babylonian Talmud, Tractate Sabbath, folio 129b, there is a curious list of dates that one is adjured to refrain from bloodletting (at the time a popular medical treatment – but with an element of risk). The Talmud provides a detailed explanation based on the power of astrological forces during that particular day and hour.

The god of War is in the Details

For those who read my brief article “Influence of the Planets and Etymology of Weekday Names in the Talmud” for Tractate Brahot 59b, you may recall the cycle of the planetary influences on both the hours of the day and the days of the week. Out of the seven ancient “planets” (Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn), there is one that the Rabbis considered dangerous: Mars.

It is therefore no coincidence that both Roman/Greek and Norse mythology attribute that planet to their god of War, the etymology of which has survived to our days of the week (Tuesday/Tyr, Martes (Spanish)/Mars).

When should you Bloodlet?

Returning to Sabbath 129b, the sage Shmuel (also considered a great medical authority in his day) advises one to only bloodlet on Sundays, Wednesdays or Fridays. He explains that Mondays and Thursdays, classic court days, are also days when the Heavenly Court assembles and therefore one should not invite undue scrutiny while taking a postponable risk (bloodletting) on a day of divine judgment. Shmuel then adds that Tuesdays should be avoided because “Mars has influence on the pairs.”

“Pairs” refers to even hours of the day, when it was thought that demons have greater influence. The combination of the power of Mars and the power of demons was thought to make such a confluence highly inauspicious for any risky undertaking, especially one like bloodletting which is related to both the themes of Mars/War/Destruction and Demons. Now we need a chart to explain how the timing works.


During daylight hours, there are four instances during the week (bolded in the chart above) where the influence of Mars falls during an even hour of the day: Monday during the 16th hour (4th hour of daylight), Tuesday during the 20th hour (8th hour of daylight), Thursday during the 14th hour (2nd hour of daylight) and Friday during the 18th hour (6th hour of daylight). There are two other instances of Mars “ruling” during daylight: Wednesday in the 24th hour, which is basically nightfall and one wouldn’t bloodlet then anyway, and the second instance is on the 22nd hour of the Sabbath when one would not bloodlet in any case.

Monday and Thursday have already been disqualified for bloodletting because of the Heavenly Court reason, so there is no need to invoke the Mars influence. But Tuesday as we can see from the chart has Mars dominant during an even hour, thus making the whole day and specifically that hour extremely dangerous.

But what about Friday? Mars also rules during an even hour on Friday, but Shmuel advises that one can bloodlet then. The answer has to do with popular practice.

After bloodletting it was common to have fish (or meat) to replenish the nutrients that were lost from the procedure. Most Jews only ate these dishes on Friday night. Hence they would save their bloodletting until Friday. Once it became popular to bloodlet on Friday the danger is mitigated as “God protects the heedless.”


At seems clear that at some point in Jewish history, the Rabbis took astrological and demonic forces quite seriously, to the point of ruling based on these beliefs. It is obvious that we know longer follow such concerns or give them any credence.

Is it a function of popular practice and therefore “God protects the heedless?”

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