Ndduy

Nidduy usually lasts 30 days. The term may be doubled or tripled. "Nidduy" could be uttered by one rabbi.

A person who has fallen under Niddui must:

• dress in mourning
• he cannot be cut
• he must stay at a distance of 4 steps from the Jews;
• he can attend the synagogue, but he cannot enter through the common gate.

The Talmud speaks of 24 reasons why a Jew can be punished by a form of excommunication of the Niddui . Maimonides lists the following:

1. if a Jew insults a learned Jew, even after his death;
2. if a Jew testifies against a Jew in a non-Jewish court, because of which the Jew loses money that would not be confiscated by a Jewish court;
3. if a Jew insults a Jewish witness in court;
4. if a Jew calls another Jew a “slave”;
5. if a Jew refuses to appear in court at the appointed time;
6. if a Jew carelessly treats any commandments of the Torah;
7. if a Jew refuses to obey a decision of a Jewish court ;
8. if a Jew holds a thing or animal in his personal property that could harm other Jews, such as a broken staircase or a wild animal;
9. if a Jew sells real estate to a non-Jew without taking into account the possible harm caused by a non-Jew to his Jewish neighbors;
10. if the priest selling the meat appropriates all the meat of the sacrificial animals;
11. if a Jew violates Shabbat ;
12. if a Jew will work the evening before Passover ;
13. if a Jew is blaspheming;
14. if a Jew forces others to defile the name of God;
15. if a Jew forces others to eat sacred meat outside Jerusalem ;
16. if a Jew independently calculates the calendar outside of Israel, and celebrates Jewish holidays in accordance with his calculations;
17. if a Jew "puts a stumbling block in the way of the blind," that is, he tempts another Jew to sin;
18. if a Jew prevents the community from performing any religious action;
19. if a Jew sells banned meat under the guise of kosher ;
20. if shokhet (resnik) forgets to show the knife to the rabbi for verification;
21. if a Jew scolds himself;
22. if a Jew marries a divorced Jewish wife for business;
23. if the rabbi becomes the object of scandal;
24. if they unjustly excommunicated anyone.

• Rabbi Akavia (end of I - beginning of II century A.D. ), who was one of the compilers of the Mishnah , underwent Niddui until his death. The reason is a disrespectful review of their teachers.