When the Baal Shem Tov returned from his attempted journey to the Land of Israel, he passed through Hungary. He arrived in the town of Szerencs on market day. In the evening, he gathered the townspeople and gave a sermon. Among his words, he said: "There are wise men who go to the market to do business, and afterward go to eat and drink, listen to music, and enjoy pleasures. Not so the fools – who, on their way to the market, before doing any business, already go to the musicians and lose their wealth and money on food, drink, and other pleasures, remaining empty-handed without a penny. Thus, they lose the market as well." The parable, of course, refers to Jews who lose the eternal world, the life of the World to Come, for the fleeting pleasures of this passing world.
During his stay in the town, the Baal Shem Tov lodged with R' Moshe Yechezkel and his wife Reizel, wealthy Jews known for their great hospitality, and they became very close to him. Before departing, he thanked his host and hostess and blessed them, asking, "What is your request?" They answered that they were childless and wanted living and lasting offspring.
The Baal Shem Tov replied that if they agreed to lose all their wealth, they would be saved with God's help. They both agreed. The Baal Shem Tov added that a son would be born to them who would illuminate the world.
Indeed, in 5511 (1751), the couple was blessed with a son, whom they named Yitzchak Isaac. However, shortly after the child was born, the father passed away, having already lost his wealth. As the child grew, he helped support his poor mother by working as a shepherd.
Later, the tzaddik Rabbi Leib Sarah's drew the young man close, and he grew to become the holy Rabbi Yitzchak Isaac of Kaliv, who wondrously served God with melody. He would take secular songs of the shepherds and elevate them to holiness.
Once, the Rebbe heard a shepherd playing a flute and singing an emotional love song: "Forest, forest, how great you are. Rose, rose, how far you are…" The Rebbe approached the shepherd, offered him a coin, and asked him to sing the melody again. When the shepherd finished, the Rebbe prostrated himself and began to sing with a heart full of longing, using the shepherd's melody but with different words: "Exile, exile, how long you are. Holy Shechinah, how far you are. If only the exile were removed, we would all be united together…"
Afterward, the Rebbe asked the shepherd to sing the melody again, but the shepherd had completely forgotten it… Then the Rebbe told his close followers that this melody was sung by the Children of Israel by the rivers of Babylon, "There we sat and wept when we remembered Zion."
It is said that when Rabbi Naftali Tzvi of Ropshitz first heard this song, he said that when the Rebbe of Kaliv sings this melody, it causes a commotion in the upper worlds, awakening the source of mercy. And groups of merciful angels come to greet the holy Rabbi Leib Sarah's (who had drawn the Rebbe of Kaliv close) in his heavenly palace, praising: "Blessed is he who gave us this precious soul."
The Rebbe of Kaliv was from the root of the soul of David, King of Israel, who was a shepherd and the sweet singer of Israel. His songs of longing sung with the elevation of the soul bring the Mashiach in actual reality. The chamber of melody is adjacent to the chamber of teshuvah (repentance), which returns the soul to the Garden of Eden and brings the entire nation and world to complete redemption
