yoreh deahfeatured in 23 works

Moser (Informer)

MOH-sir (plural: muh-SEEM)

A Jew who reports fellow Jews to non-Jewish authorities—a figure treated as a serious betrayer in Jewish law.

In Jewish tradition, the moser (informer) is someone who breaks ranks with the community by reporting another Jew to outside authorities—non-Jewish courts, rulers, or officials. This wasn't seen as a simple act of honesty; it was understood as a profound breach of trust and communal solidarity. The rabbis debated intensely: when, if ever, was such reporting justified? Could you report a fellow Jew who had committed a crime? What if they had harmed you personally?

The tension here reflects a real dilemma communities face. Jewish law wanted to protect its members from external persecution, but it also needed to address genuine wrongdoing. Over time, the tradition developed nuanced rules. A moser wasn't automatically condemned if the person being reported had already caused direct, irreversible harm, or if the report prevented future damage. But reporting someone for financial disputes or minor infractions—going to an outside court instead of a Jewish court—was considered betrayal, a violation of the principle that the community should handle its own affairs.

The concept also touched on identity and power: it mattered who held authority. In medieval Europe, where Jews had limited legal rights, reporting to hostile authorities was far more serious than in later, more integrated societies. The rules evolved as Jewish life changed, but the core idea persisted—that there was a difference between loyalty to law and loyalty to community, and that informing required careful moral accounting.

How it traveled

Bava Kamma
Sura (Babylonia) · 500
explains
Teshuvot HaGeonim (Harkavy)
Sura (Babylonia) · 900
explains
Mishneh Torah, One Who Injures a Person or Property
Fostat (Old Cairo) · 1180
explains
Mishneh Torah, Repentance
Fostat (Old Cairo) · 1180
explains
Kol Bo
— · 1250
explains
Sefer HaChinukh
Barcelona · 1300
explains
Meiri on Bava Kamma
Perpignan · 1300
redefines
Teshuvot HaRosh
Toledo (Castile) · 1325
explains
Tur
Toledo (Castile) · 1335
explains
Sefer HaTashbetz
Tunis · 1430
explains
Nimukei Yosef on Bava Kamma
Spain (medieval) · 1450
explains
Shulchan Arukh, Choshen Mishpat
Tzfat · 1565
explains
Avkat Rokhel
Tzfat · 1565
explains
Darkhei Moshe
Krakow (Cracow) · 1570
explains
Haggahot Chadashot on Sefer Mitzvot Katan
Posen (Poznań) · 1580
explains
Siftei Kohen on Shulchan Arukh, Choshen Mishpat
Vilna (Vilnius) · 1646
explains
Turei Zahav on Shulchan Arukh, Yoreh De'ah
Lviv (Lemberg) · 1646
applies
Ba'er Hetev on Shulchan Arukh, Choshen Mishpat
Prague · 1700
explains
Shulchan Arukh HaRav
— · 1795
explains
Pele Yoetz
Silistra · 1815
explains
Kitzur Shulchan Arukh
Ofen (Buda / Budapest) · 1864
explains
Arukh HaShulchan
Novardok (Novogrudok) · 1884
explains
Kaf HaChayim on Shulchan Arukh, Yoreh De'ah
Jerusalem · 1900
explains

Key passages(20)

Bava Kamma 113:2:21↗explains

Bava Kamma · Anonymous (Stammaim, redactors of the Bavli) · 450 CE