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Shabbos 79b

שבת ע״ט ע״ב

Shabbat 79b

Learn Shabbos 79b step by step: Aramaic beside English, every question, answer and proof colour-coded.

Open Shabbos 79b in Gemara Clarity

Topic

The amount of קלף and דוכסוסטוס for carrying on שבת, and רב's ruling on which hide may be used for תפילין and מזוזה

Overview

The גמרא starts with the משנה's rule that carrying קלף on שבת makes you liable once there is enough to write the shortest פרשה of תפילין. A ברייתא seems to say 'enough to write a מזוזה.' The גמרא settles this by reading the ברייתא as giving a separate amount for each material: a מזוזה for דוכסוסטוס, and שמע ישראל for קלף. Then רב rules that דוכסוסטוס is like קלף, so תפילין may be written on it. The גמרא challenges רב several times. It answers that the sources describe the ideal way (למצוה), or speak about a מזוזה, or reflect a מחלוקת תנאים. Proposed proofs for רב, from תנא דבי מנשה and from worn-out תפילין, are each rejected. Since רבי מאיר wrote a מזוזה on קלף, the גמרא finally rereads רב to mean that קלף, like דוכסוסטוס, is valid for a מזוזה. The amud ends by quoting the next line of the משנה, about ink.

Opening lines

קְלָף כְּדֵי לִכְתּוֹב עָלָיו

Parchment: enough to write on it

פָּרָשָׁה קְטַנָּה.

a short passage.

וּרְמִינְהוּ,

And they raised a contradiction:

קְלָף וְדוּכְסוּסְטוֹס

Parchment and dokhsostos:

The steps (26)

  1. StatementThe משנה's amount for parchment
  2. ChallengeA ברייתא gives a different amount
  3. Resolution'Mezuzah' means the mezuzah passage inside tefillin
  4. ChallengeAre tefillin ever called 'mezuzah'?
  5. ProofProof: רבי זכאי calls the tefillin passages 'mezuzah'
  6. ChallengeThe ברייתא's own second half shows it means a real mezuzah
  7. ResolutionEach material gets its own amount
  8. Statementרב: dokhsostos is like parchment for tefillin
  9. ChallengeThe משנה mentions only parchment for tefillin
  10. ResolutionThe משנה describes the best way
  11. ChallengeA הלכה למשה מסיני assigns tefillin to parchment
  12. ResolutionThis too describes the best way
  13. Challenge'If he deviated, it is invalid'
  14. ResolutionThat rule is about a mezuzah
  15. Challenge'Deviated in this or that' includes tefillin
  16. ResolutionBoth cases are about a mezuzah
  17. ResolutionA second answer: it is a dispute of תנאים
  18. Resolutionרב פפא: רב follows תנא דבי מנשה
  19. ProofWhich item does the ברייתא mean: מזוזה or תפילין?
  20. RejectionThe ברייתא is about a ספר תורה
  21. ProofA second proof for רב from worn-out תפילין
  22. RejectionThose תפילין were written on קלף
  23. ChallengeCan a מזוזה be written on קלף?
  24. Resolutionרבי מאיר wrote a מזוזה on קלף
  25. Conclusionרב's statement is reread as being about מזוזה
  26. Statementמשנה: the measure for ink