(OH 44, Magen Avraham subparag. 5)
If a Sefer Torah falls by accident, is there an obligation to atone by fasting? Is there a basis for the widespread belief that people are obligated to fast for forty days?
The custom of fasting when a Sefer Torah falls does not appear in the Talmud or in the literature of the Rishonim. Rabbi Moshe Zacuto of Italy is the first to mention this custom in 1662. Rabbi Abraham Gombiner (Poland 1637-1683), is probably the halakhic authority who established the custom of fasting after the fall of a Sefer Torah. Since the time of these authorities, fasting became an accepted custom among many halakhic authorities, but they differed greatly as to how the fast should be observed. Some authorities proposed other ways to atone, among them reciting Psalms, buying a new Torah mantle, giving tzedakah and learning special passages.
The Jewish People has always greatly honored the Sefer Torah. As a consequence, the fall of a Sefer Torah is considered a very serious incident, which shocks all those present. Even so, there is no clear basis to oblige even the person who dropped the Torah to fast. In general, one should rule according to R. Hayyim Yosef David Azulai (1724-1806) who said that the “local rabbi should rule as he sees fit in order that they should be careful in the future, and everything [should be decided] according to the time and place”.
Specifically, one should prefer the approach of R. Moshe Greenwald (ca. 1912) who ruled that one should perform acts of atonement related to what happened. Such acts would include buying a new mantle for the Sefer Torah which fell, studying the laws of the Sefer Torah, and briefing anyone who holds the Sefer Torah or lifts it so that this sad mishap should not recur.
Rabbi David Golinkin