Tens of thousands of Jews are marking the 210th anniversary of the first Chabad Rebbe’s release from prison with festive Chasidic gatherings worldwide.

Rabbi Schneur Zalman of Liadi was arrested by Russian authorities shortly after the publication of the Tanya, the seminal work of Chabad-Lubavitch thought that opposing groups mischaracterized as subversive to the ruling regime.

He was released on the 19th day of the Hebrew month of Kislev, which began this year on the night of Dec. 15. …