In the year 5679 (1918), in the wake of the first World War, there were no etrogim, for it was not possible to bring them from outside the country. Only the Rebbe Rashab (Rabbi Sholom DovBer of Lubavitch, 1860-1920) who lived at that time in Rostov, had one, thanks to the efforts of one of the chassidim. Obviously, everyone in the city went to make a blessing on the Rebbe’s etrog and everyone made the blessing in the Rebbe’s presence.

One chassid arrived in Rostov on Chol HaMoed Sukkot to pronounce a blessing on the etrog. After he had fulfilled the mitzvah, the chassid said with joy and satisfaction, "Ah, thank G‑d!" The Rebbe said to him: "May the Almighty make the joy of the mitzvah shine for the whole year."