Unholy Cow

https://www.youtube.com/watch?v=D9nE894ORAs

The fast of the 5^th month (colloquially known as the 9^th of Av in Rabbinical circles) mourns the destruction of the temple. However, the reasons for its destruction and continuance of this state are not widely understood.

In the late 2^nd temple period, the Pharisee sect were battling the Temple and the priests to take over the Temple services, and enforce their new religion on the majority of Israel. The greatest foe of the Sadducees Rabban Yochanan ben Zakkai, was leader of the Perushim.

The Torah prescribes several steps in the preparation of the Red heifer ashes. At each step, the Priest becomes impure until nightfall, e.g.:

B’Midbar - Num:19

7 Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he may come into the camp, and the priest shall be unclean until the even.

8 And he that burneth her shall wash his clothes in water, and bathe his flesh in water, and shall be unclean until the even.

This practice had been kept by the Priests since Eleazar, mentioned in the book of Numbers. The rabbis  wished to challenge the priesthood, in order to take power for themselves (or vice versa depending on one's allegiance). Thus, they devised a new law, which said that – contrary to the Torah – the Priest becomes pure in the day, simply from dipping in a mikveh. This is in violation of the plain meaning of the Torah, but that is no problem for the rabbis, as they claimed to have a tradition from their fathers! This later evolved into an alternative unwritten book they claimed was given on Sinai, and they called it the oral Law. Of course, this was to be written as the Mishnah, and the  claim to its origins used buttress their new religion.

The following mishna and the Tosefta (addition to the Mishnah) describe what tactics he used to destroy the priesthood, and eventually the Temple.

Mishna Parah 3: 7

MISHNAH 7. IF THE COW REFUSED TO GO OUT, THEY MAY NOT TAKE OUT WITH IT A BLACK ONE LEST IT BE SAID, ‘A BLACK (COW] HAS BEEN SLAIN’ NOR ANOTHER RED [COW] LEST IT BE SAID, ‘TWO HAVE BEEN SLAIN’. R. JOSE STATED: IT WAS NOT FOR THIS REASON BUT BECAUSE IT IS SAID IN SCRIPTURE AND HE SHALL BRING HER FORTH, BY HERSELF. THE ELDERS OF ISRAEL USED TO PRECEDE THEM ON FOOT TO THE MOUNT OF OLIVES, WHERE THERE WAS A PLACE OF IMMERSION. THE PRIEST THAT WAS TO BURN THE COW WAS (DELIBERATELY] MADE UNCLEAN ON ACCOUNT OF THE SEDDUCEES: IN ORDER THAT THEY SHOULD NOT SAY, ‘ONLY BY THOSE ON WHOM THE SUN HAS SET MUST IT BE PREPARED

Tosefta Parah 3:7 /2:8

So the Perushim would intentionally sabotage the purity of the High Priest in order to eliminate the priesthood and install their own cronies. All of this based on a mistaken  reading of the Torah.

However, the story does not end here. In the Tosefta, it quotes the Priest complaining to ben Zakkai, and then saying that the Priest was buried 3 days later. This formula repeats itself several times throughout the Mishna and Talmud. What it means is that the "curse" of rabbis resulted in the death of the Kohanim. The method here is not specified - it may have been a real curse or something less heavenly.  It would certainly be a good idea to avoid such curses.

 During the festival of Sukkoth, there was a similar battle over the non Biblical feast of “Simchat Beit Shoevah”. There, the Pharisees encouraged the masses to pelt the Priest with Etrogim. The Talmud does not consider group murder as being punishable as murder, so this loophole, created by the Tannaim [rabbis of the mishnah] served them well in assassinating the Priesthood.

This High Priest was possibly King Alexander Janneus, who did not take well to this attack, and it resulted in a brutal civil war between Janneus and the Pharisees. 

This war in Israel's holy space, the temple and its priests, was the internal destruction of the Temple.
Furthermore, the internal hatred and civil war led to the spiritual and physical weakening of the Israelite state.

Take home lesson: keep disputes civil and do not turn them into wars - this only strengthens the enemy.