Question: Is the Talmudic expression "a part of a day is equal to a whole" universal?
Dear Rabbi Erkin,
Is the Talmudic expression "a part of a day is equal to a whole" intended to be universal or are there certain contexts which limit its application? For instance, both Moses and Elijah fasted for 40 days and 40 nights. Is it possible to use the above figure of speech and say they fasted five minutes at the end of day 1, all of the following 38 days and five minutes at the beginning of day 40 making, actually, a total of 38 days and ten minutes?
Thank you, John
Answer: Dear John,
The Talmudic passage you refer to is in the Talmud Pesachim 4a.
This idea of "a part of a day is equal to a whole" is a concept that largely applies to certain practices within the Jewish laws of mourning.
Two examples that readily come to mind:
When a person is sitting 'shiva', the seven day mourning period for close relatives, the seventh and final day of mourning actually concludes early in the morning due to the principal that "a part of a day is equal to a whole" - e.g. after observing the laws of mourning for an hour or so of the last day - one can then call the day 'completed' and formally conclude the shiva period.
Similarly, there is a 33-day period of communal mourning which commences from the second day of Passover and concludes on the mini-holiday known as Lag B'aomer. Here too - one need not wait until the actual conclusion of the 33rd day, rather, once one has 'mourned' for a short period of time on this last day, one is then released from any further mourning obligations.
In the particular cases that you mention - I subscribe to the opinion that they literally fasted for 40 complete days and nights, but that indeed, this was only possible by Divine intervention. Heck, if He can split the sea, then He can also ensure that these two righteous people didn't starve to death.
Rabbi Ari Enkin
Ramat Beit Shemesh, Israel