Yom Kippur, Hebrew Yom Ha-Kippurim is the most solemn of Jewish religious holidays when orthodox Jews focus on the expiation of sins and a desire to have reconciliation and relationship with God. Yom Kippur concludes the “10 Days of Repentance” (Awe) that begin with Rosh Hashana (New Year’s Day). It is observed on the 10th day of the lunar month of Tishri (September and October)