When Rabbi Menachem Mendel of Lubavitch (the “Tzemach Tzedek,” 1789–1866) was in Petersburg to attend the rabbinical convention of 1843, he received a special permit from the Russian minister of war to address the Jewish soldiers serving at the military installation in nearby Kronshtadt.
(This was in the days of the infamous “Cantonist” decree, when by order of Czar Nicholas I, six- and seven-year-old Jewish children were conscripted into the Russian army for a period of twenty-five years and indoctrinated into Christianity, G‑d forbid. The fact that the rebbe was granted permission to address the Jewish soldiers at Kronshtadt was nothing less than a miracle, since the primary purpose of their conscription was to tear them away from their faith.)
When the rebbe arrived, he was greeted by the waiting soldiers, who said to him: “Rebbe! We’ve been toiling all morning to prepare for your coming, polishing our buttons in your honor. Now it’s your turn to work hard: polish our souls, which have been dulled and coarsened by our many years of disconnection from Jewish life.”
Following his address, in which he encouraged their heroic efforts to cling to their faith, the rebbe said: “You polished your buttons with sand and water. The soul, too, is polished with sand and water: with the holy letters of Tehillim (Psalms) recited with a generous infusion of tears.”
One of the soldiers spoke up: “But Rebbe, battles are won with joy, not tears.”
“So speaks a soldier!” said the rebbe, with obvious satisfaction. “Yes, you’re right. A soldier enters the fray of battle to the tune of a joyous march, not with tears. It is by the power of his joy that he is victorious even in the most dangerous and challenging endeavors.”