The Chafetz Chaim and the Mishnah Berurah

Rabbi Yisrael Meir ha-Kohen Kagan was born in 1839 and lived in Radin, a small town near Vilna, keeping a shop his wife largely ran and closing early once the day's needs were covered.

In 1873 he published anonymously a book called Chafetz Chaim, after the verse 'Who is the man who desires life... guard your tongue from evil' (Psalms 34:13–14). It was the first systematic code of the laws of lashon ha-ra, harmful speech: what may be said about a person, what may not, when gossip becomes forbidden, and when one is obliged to warn. Scattered through the Talmud and ethical literature, these rules he assembled with the rigour normally applied to kashrut.

His second life's work was the Mishnah Berurah, a commentary on Orach Chaim, the section of the Shulchan Aruch that governs daily life — prayer, Shabbat, festivals. Six volumes appeared between 1884 and 1907, digesting three centuries of later opinion and giving a clear practical ruling in each case. For the Ashkenazi world it became decisive.

He also wrote Shmirat ha-Lashon; Machaneh Yisrael, a booklet for Jewish soldiers in the Russian army; and Likutei Halachot on the sacrificial order, since he expected the Temple to be rebuilt in his lifetime. He died in 1933, a founder of Agudath Israel.