Shavuot 23 - 29
No Sleeping and No Eating
Rabbi Yochanan said, “One who makes an oath to not sleep for three days receives lashes, and he is permitted to sleep immediately.”
This person has made a shevuat shav — a vain oath — since his words state that he is committing himself to something that is known to be impossible. (Rashi) In the words of the gemara above (21a): “A vain oath is when a person makes an oath to change that which is known to man [to be true]. He has transgressed the Torah prohibition: “You shall not take the name of the L-rd, your
The gemara asks a question on Rabbi Yochanan’s statement from our mishna that teaches that the oath one makes “not to sleep” is a valid oath called a shevuat bitui. (Vayikra 5:4) The gemara answers that in Rabbi Yochanan’s case he explicitly states that he won’t sleep for “three days,” which is impossible, whereas the mishna’s case does not specify a time limit, and therefore his oath is to not sleep only as long as it is possible for him to stay awake. (Tiferet Yisrael)
It is evident, however, that the gemara first thought that an oath “not to sleep” would mean “forever.” Based on this “first thought” Tosefot asks why the gemara didn’t pose this exact same question on the mishna above (19b) that teaches that an oath “not to eat” is a valid shevuat bitui. It should be an invalid shevuat shav — vain oath — since the phrase “not to eat” seems to imply “not to eat forever.” This is certainly impossible and not a valid oath.
Tosefot offers two answers. One is that the gemara did not ask this question above because it was clear to the gemara that an oath “not to eat” is not to be mistaken to mean “not to eat forever,” unlike an oath “not to sleep” that could be understood as “not to sleep forever” — as the gemara first understood it on our daf. (Tosefot does not elaborate on why we would not mistakenly understand the case of not eating to mean “forever,” as opposed to our gemara mistakenly understanding not sleeping to mean “forever.”)
The second answer given by Tosefot is that it is possible to understand the above mishna as speaking about a case of an oath “not to eat forever,” but is dealing with a very specific case of not eating a clearly designated loaf of bread that is in front of the person making the oath.
The Ran discusses the status of an oath “not to eat for thirty days.” Is it similar to an oath “not to sleep for three days” — and therefore a vain oath — or not, and therefore a valid oath? He suggests that there is possibly a distinction between the two oaths, despite the fact that both scenarios are “impossible.” Although an oath not to sleep for three days is clearly “in vain,” perhaps an oath not to eat for thirty days is not “in vain.” An oath to not sleep for three days is in vain since the person will certainly sleep within three days. However, an oath not to eat for thirty days might obligate the person to refrain from eating only until his life is endangered, at which time the concept of pikuach nefesh — saving life — obligates him to eat, at least as much as necessary to sustain his life.
The Ran also cites the ruling of the Rambam, who equates not eating and not sleeping, and rules that if a person made an oath not to eat for seven days (Laws of Oaths 5:20), the oath is in vain and invalid. The Ran concludes that despite the distinction between the two cases which he proposed, the halachic ruling is indeed in accordance with the Rambam, that neither oath is valid. However, unlike the Rambam who reasons that “not to eat for seven days” is impossible and therefore “in vain,” the Ran explains that this oath is invalid for a different reason. An oath to not eat for this time period is invalid, says the Ran, since these words constitute a commitment to starve himself to death, which is an “oath to transgress the words of the Torah” — to “guard yourselves very well…” (Dev. 4:15) — and is thereby an invalid oath.
- Shavuot 25b