The Fast and the Horse
A Rav's secret fasting grew so severe that the Baal Shem Tov ran to stop it, and his horse died on the road.
A story ofRav Yaakov Yosef HaKohen Katz of Polnoyהרב יעקב יוסף בן צבי כץProfile ›
It is told that while Rav Yaakov Yosef served as Rav of Rashkov, he took on a fast that no one in his home knew about. He ate nothing by day, and once a month he went from one Shabbos to the next without food. Only a young niece, an unmarried girl, shared the secret. She brought him a meal when no one was watching and cleared the dishes away, so the family would suspect nothing. For five years he lived this way.
In the sixth year the Baal Shem Tov was on the road when he heard a call telling him to run to the Rav at once, because that very day his mind would be lost to him. He ran so hard that his horse dropped dead on the way, an animal worth ten gold coins. He said to the Rav, “My horse died on your account. Let it be an atonement in your place.” The Rav ate immediately, and from then on he listened to the Besht.
The Baal Shem Tov also sent him a letter. He wrote that this kind of fasting grows from a dark and heavy mood, and that the Shechinah rests on a person through the joy of a mitzva, never through gloom. He advised him, each morning as he learned, to cling to the letters with full devotion, so that harsh judgments would be sweetened at their root, and never to turn away from his own body by fasting beyond what duty requires. “If you listen to me,” he closed, “Elokim will be with you.”
Source: Shivchei HaBesht (Kopust, 1815), section 22 (Sefaria: Shivchei HaBesht 22), including the Baal Shem Tov's letter to the Rav of Nemirov; told there in the name of Rav Yoel of Nemirov.
Strong commitment can slide into harshness without our noticing. Today, look at one thing you do for Hashem, whether a fast, a long stretch of learning or a strict habit, and ask whether it brings you joy or only strain. If you are wearing yourself down, ease it a little and add something that makes the mitzva warm: a song before you learn, a kind word at the table, an earlier night. Avodah that leaves you whole is what the Baal Shem Tov wanted for his talmid. If you are unsure where the line is, ask a rav.