Study Shabbat folio 34B with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
Text Excerpt
מפני מה אמרו אין טומנין בדבר המוסיף הבל ואפילו מבעוד יום? גזירה שמא יטמין ברמץ שיש בה גחלת. אמר ליה אביי: ויטמין? גזירה שמא יחתה בגחלים.
Why did the rabbis say that one may not insulate hot water for Shabbat in something that adds heat, even while it is still day? It is a decree lest one come to cover it in hot ashes that contain a glowing ember. People may not differentiate between addition of heat by means of hot ashes and other additions of heat. Abaye said to him: Let him insulate it with hot ashes, what is the problem? Rava answered him: It is a decree lest one come to stoke the coals in order to make them burn on Shabbat and thereby violate a Torah prohibition.
תנו רבנן: בין השמשות ספק מן היום ומן הלילה, ספק כולו מן היום, ספק כולו מן הלילה — מטילין אותו לחומר שני ימים.
A baraita states a baraita which discusses the range of problems that arise with regard to the twilight period. Twilight is a period of uncertainty. It is uncertain whether it consists of both day and night, it is uncertain whether it is completely day, and it is uncertain whether it is completely night. Therefore, the rabbis impose the stringencies of both days upon it. If there is a stringency that applies on either of the days, one is obligated to adhere to it during the twilight period.
ואיזהו בין השמשות? משתשקע החמה כל זמן שפני מזרח מאדימין. הכסיף התחתון ולא הכסיף העליון — בין השמשות. הכסיף העליון והשוה לתחתון — זהו לילה, דברי רבי יהודה. רבי נחמיה אומר: כדי שיהלך אדם משתשקע החמה חצי מיל. רבי יוסי אומר: בין השמשות כהרף עין, זה נכנס וזה יוצא, ואי אפשר לעמוד עליו.
Nevertheless, the definition of twilight is uncertain. And what is twilight? From when the sun sets, as long as the eastern face of the sky is reddened by the light of the sun. If the lower segment of the sky has lost its color, and the upper segment has not yet lost its color, that is the twilight period. If the upper segment has lost its color, and its color equals that of the lower one, it is night; this is the statement of R' Yehuda. R' Neḥemya says: The duration of the twilight period is the time it takes for a person to walk half a mil after the sun sets. R' Yosei says: Twilight does not last for a quantifiable period of time; rather, it is like the blink of an eye: This, night, enters and that, day, leaves, and it is impossible to calculate it due to its brevity.