The second mishna in mesechet berachot writes:

From when may one recite Shema in the morning? From when one can distinguish between Tekhelet [purple-blue wool] and white. Rabbi Eliezer says: [The earliest time for Shema is when one can distinguish] between Tekhelet and the color of leek, and one must finish reciting it by sunrise. Rabbi Yehoshua says: [One may recite Shema] until three hours [of the day], for such is the way of the sons of kings, to arise at the third hour. If one recites [Shema] later than this, he has not lost out, [but rather is] like one who reads the Torah.

The Artscroll Talmud Bavli quotes the Rambam's Commentary on the Mishna on daf 9b note 24:

For since most people rise by sunrise, it signifies the end of the "time of rising".

Since, we no longer follow the pattern of the sun but the pattern of our alarm clocks, and many folks, especially college students, tend to sleep past noon at times, why don't we change the "time of rising" to mean when the college students get up?

We also have people working night shifts which changes this whole logic altogether...


3 Answers 3


R. Yechiel Michel Epstein addresses the related question of why the times for Shema are dependent on sha'ot zemaniot, if the Torah relates it to lying down and getting up which don't necessarily change based on the length of sha'ot zemaniot. In his answer to this question he also touches upon why the times can never change:

Aruch Hashulchan O.C. 58:12-13

מיהו יש בזה שאלה דנהי דודאי לכל דיני התורה כן הוא מ"מ לענין ק"ש דכתיב בה ובשכבך ובקומך הלא השכיבה והקימה לא ישתנו בהתארך היום או יתקצר כלומר כשהיום והלילה שוים הוי זמן ק"ש עד אחר שעה תשיעית דהם ג' שעות על היום משום דבני מלכים ישנים עד ג' שעות וא"כ אטו בתקופת תמוז שרביע היום הוא בחצי שעה שמינית יקומו אז הבני מלכים הרי הם ישינים עד אחר שעה התשיעית וא"כ ליהוי זמן ק"ש תמיד עד אחר שעה תשיעית שהרי קרינן אז ובקומך וראיתי לאחד מן הגדולים שעלה על דעתו לומר כן [משכנות יעקב סי' ע"ו וכתב אלולי דמסתפינא ע"ש] אמנם באמת אין זה שאלה כלל ודיני התורה לא ישתנו לעולם כלומר לראות לפי מנהג המקום והדברים התלוים ביום ובלילה צותה לנו התורה שכל אחד במקום שהוא כשאצלו יום ינהוג דיני יום אף שבמקום אחר הוי לילה וכשאצלו לילה ינהוג דיני לילה אף שבמקום אחר עדיין יום ועל זה נאמר שבת היא לה' בכל משבתיכם כלומר תקבלו השבת בכל מקום שאתם יושבים שכשבמקומכם יום הששי הגיע הלילה אצליכם שבת אף שבמקום אחר עדיין הוא יום ששי ולהיפך בשבת בערב כשהוא לילה אצליכם חול אף שבמקום אחר עדיין הוא שבת וכן גבי ק"ש שהתורה אמרה ובשכבך ובקומך אינו תלוי בכל אדם מתי שישכב ומתי שיקום אלא זמן שכיבה לרוב העולם וזמן קימה לרוב העולם ושיערו חז"ל שבזמן הנץ רוב העולם קמים ממטתם ויש שקמים מעמוד השחר ובני מלכים ישנים עד ג' שעות שהוא רביעית היום ואין משגיחים על מה שיש כמה ערים שבנץ החמה עדיין כולן ישינים וכיוצא בזה ולפ"ז הוי כאלו התורה אמרה שבנץ החמה תקרא ק"ש ועד רביע היום הוה זמן ק"ש ואז ממילא דבכל מקום ומקום לפי מה שעומד בכדור הארץ כששם תנץ החמה הוה זמן ק"ש וכששם יעבור רביע היום עברה זמן ק"ש כמו בשבת ולא משגחינן אם שם כבר עמדו או עדיין ישנים דלא לפי מנהג בני אדם ניתנה התורה אלא גזירה היא כך וכך תעשה ביום ובלילה וממילא שכל אחד מתי שהוא אצלו יום הוה מצות היום עליו ובלילה מצות הלילה עליו

However, there is a question with this: Granted that this is certainly true with regard to all the laws of the Torah, nevertheless regarding Keriat Shema where it is written "when you lie down and when you get up", the [times of] lying down and getting up don't change with the lengthening or shortening of the day. That is to say that when the day and night are equal [i.e. twelve hours each] the time for Keriat Shema would be until after 9:00 which is three hours into the day, for the children of kings sleep until three hours into the day. If so, during the summer when a quarter of the day is 8:30, do the sons of kings get up [at 8:30]? They still sleep until after 9:00! So the time for Kerias Shema should always be until after 9:00, because that is when it is called "when you get up". And I saw one of the great [rabbis] who thought to say this (Mishkenot Yaakov # 76, and he wrote "if I was not afraid", see there).

However, in truth this is not a question at all, and the laws of the Torah never change, meaning, to look at the practice of the locale. For the things that are dependent on day and night the Torah commanded us that each individual — in the place where he is — when it is day for him he should observe the laws of day even though elsewhere it is night. And when it is night for him he should observe the laws of night even though elsewhere it is still day. And about this it was said "it is Shabbat for God in all of your dwelling-places", meaning that you should accept Shabbat in any place where you are dwelling such that when in your place on Friday the night arrives it is Shabbat for you even though elsewhere it is still Friday. And conversely on Saturday in the evening when it is night, for you it is non-Shabbat even though elsewhere it is still Shabbat.

And so too by Kerias Shema, where the Torah said "when you lie down and when you get up", it is not dependent on when the individual person lies down and gets up. Rather, it is [based on] the time of lying down for the majority of the world, and the time of getting up for the majority of the world. And the Sages assessed that at the time of sunrise most of the world gets up from their beds, and there are some who get up at dawn, and the sons of kings sleep until three hours [into the day] which is a quarter of the day. And we don't care that there are many cities where everyone is still sleeping at sunrise, or the like.

Accordingly, it is as if the Torah said that sunrise is when you should read Shema, and until a quarter of the day is the time for Keriat Shema. And then automatically, in each place depending on where it is located on the globe, when the sun rises there it is the time for Keriat Shema, and when a quarter of the day passes there the time for Keriat Shema passes, just like by Shabbat. And we don't care if there they already got up or are still sleeping because the Torah was not given according to the practice of the people; it is simply a decree [that] such-and-such you do by day or by night. And automatically whenever it is day for each individual the day mitzvot are upon him, and at night the night mitzvot are upon him.

To be honest, though, I'm not sure I really understand how this explanation addresses the issues. You can see more about that in my related question.


Once Chazal set the time, I don't know of anyone that really tried to change it; not that they would have the authority to do so.

I once asked R' Rieder at Aish HaTorah why the morning shema was limited only to the first three hours of the day even though people sleep in; while the night shema extended all night. He answered that it should apply all day also, but Chazal limited it only to the first three hours. This fits with the rule that Chazal can uproot a positive mitzvah if it may cause trouble to the generation(like forbidding shofar on rosh hashana when it falls on shabbat). I think sleeping in all day is trouble enough to warrant limiting kriat shema only to the first three hours of the day by Chazal.

  • Mishnah (Berachot 10b): אם כן למה נאמר ובשכבך ובקומך בשעה שבני אדם שוכבים ובשעה שבני אדם עומדים. Why wouldn't the reason why it was limited to the first three hours simply be that the first three hours is the שעה שבני אדם עומדים? The night Shema extends all night because all night is the שעה שבני אדם שוכבים (as explained by Rashi on 9a that according to Rabban Gamliel it means the time that people are sleeping, not only the time that people go to sleep).
    – Alex
    Commented Feb 7, 2019 at 20:21
  • @Alex Then the same logic should be applied to the morning shema; the time when people stand up(which, nowadays, and probably then but less so, can be until the early afternoon). Even kings are a miut of the population; so too, people that sleep in. It just bothered me and the answer above makes sense to me. I don't expect it to do the same for others. But if anyone was inclined to think about it, I put it out there because I think it's true. Commented Feb 9, 2019 at 20:54
  • See Kessef Mishneh Hilchot Keriat Shema 1:13.
    – Alex
    Commented Feb 24, 2019 at 18:44

You should read Rabbeinu Bartenura's commentary on the Mishnah, esp. the last few sentences.

I'll summarize the main point. He explains that when Rav Yehoshua says "3 hours", it really means 1/4 of the day, and 3 hours is used as a phrase assuming that the length of the day and night are equal. Hence, "hours" are sha'ot z'maniyot. I.e., the length of the "hour" varies based on the season and your location. Likewise, when speaking about the king's rising, it also changed based on the season. In short, as you hinted, the calculation was based on sunrise / sunset. These calculations are still used for numerous halachic items that are time-based - all the other davening times, and, esp. Shabbat / Yom Tov starts / ends.

The end time for Kri'at Shema follows the sha'ot z'maniyot method and not a fixed time method as dictated by alarm clocks or noon college student arousal.

In short, the concept in your suggestion would require a drastic redefinition of how Rabbanan defined "hours" with regard to the daily requirements and it would affect many other timed practices as well. I don't think it's such a simple thing to change that definition.

  • 1
    The question might best be approached by re-evaluating the times, rather than the methodology of hours. We could say that during the summer, most are noheig to wake later than during the winter for example. Commented Jul 10, 2015 at 15:24
  • Changing this one doesn't mean changing anything else. You don't even have to change the type of hour used. Just make it solar-noon instead of solar-1/4.
    – Double AA
    Commented Jul 10, 2015 at 15:39
  • @DoubleAA From Wikipedia - "Solar noon is when the sun crosses the meridian and is at its highest elevation in the sky, at 12 o'clock apparent solar time. The local or clock time of solar noon depends on the longitude and date." Thus, according to this definition, if accurate, sola noon still fits into the sha'ot z'maniyot method, as it is not exactly 12 noon at all times.
    – DanF
    Commented Jul 10, 2015 at 16:20
  • 1
    @DanF I know. That's why I said it. You are probably more familiar with the term "Chatzot" for the same event.
    – Double AA
    Commented Jul 10, 2015 at 16:22
  • I think DoubleAA's point is that you don't have to change the definition of an "hour." Just make the zman be 4 or 5 (or 6) sha'ot zemaniot into the day rather than 3.
    – Daniel
    Commented Jul 13, 2015 at 17:22

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