We find that the avos m'lachos (classes of forbidden activity on shabas) are based upon the labors associated with the mishkan (tabernacle) in the mishna (e.g. Shabas 11:6) and g'mara (e.g. Shabas 97). This question assumes that the construction of the mishkan and not the service therein was the basis for the archetypal m'lachos.

Considering how much metal work the construction of the mishkan and its accouterments entailed, why are there not avos m'lachos like mining, pounding, smelting, and vigorously applying a bellows?

This is considering that we have other m'lachos such as dash and borer that the g'mara seems to tell us are only listed separately because they were procedurally distinct in the mishkan preparation even though they are functionally equivalent. Otherwise, I might conclude that since the acts involved in producing metal structural elements for the mishkan would de facto be forbidden because they fall under other categories they didn't need their own.

  • But we do! Bishul, Boneh, Soser, and Makeh BePatish are all relevant. The issue is that the "sidurah dimateches" overlaps with "sidurah depas" and the other ones. It's not expedient to demarcate an additional seder that's already contained in the existing avos melachos. Mar 7, 2016 at 14:40
  • @IsaacKotlicky "Expedient"? What does that mean here? Defining Avos as opposed to Toldos is relevant for rules about Shegagos etc. This is not just a word game of what do we want to call it.
    – Double AA
    Mar 7, 2016 at 14:47
  • @IsaacKotlicky Please see my last paragraph. It does not appear that Chaza"l were optimizing for number of avos. Can you write your answer up as an answer with a source? If that part of your premise undermines my assumption it could be the right answer.
    – WAF
    Mar 7, 2016 at 14:54
  • If I had sources on hand for this, I would gladly write it up as an answer. Alas, this is somewhat supposition (aided by the Rambam's interpretation of Bishul). On the contrary, the top of 74a makes clear that they ARE optimizing for a given number. It appears the issue is defining כל מילתא דהויא במשכן. You are claiming this is everything involved in the CONSTRUCTION, but it seems from Chazal's choices that they're counting the MAINTENANCE of the Mishkan. The kelim, having already been built, wouldn't require further work. Replacing begadim used for service and baking bread occurred daily. Mar 7, 2016 at 15:03
  • @WAF 39 is the goal number, as it's the number of things listed as done in the construction (cf Exo 35)
    – Double AA
    Mar 7, 2016 at 15:58

1 Answer 1


The Rambam says in Hilchos Shabbas 9,6 that smelting metal is a tolada of bishul, which does not answer your question.

It would seem that activities that could only be performed by the king or large organisations, such as quarrying, are not included in the 39 melachos which relate to the average individual's cessation from work.

Alternatively these activities may not be avos because the purpose of avos is to bring artifacts to a state where they are available for human consumption (in the broader sense of the word).

Because the end products of smelting, quarrying, etc. are far removed from human consumption we have not yet identified an av melacha.

  • But then why is burning fire an Av Melakha? See biu.ac.il/JH/Parasha/veyakhel/kla.html and the Seforno, Chizkuni, etc.
    – Double AA
    Mar 7, 2016 at 0:50
  • @DoubleAA Technically one gets hana'ah from fire, and this is "human consumption." But his reference to the Rambam does have a place here - the melachos involved with making the kelim already are part of existing Avos. It would be redundant to list them separately. Mar 7, 2016 at 14:45
  • @IsaacKotlicky I don't know in what sense you use the word "technically" nor do I have any feel that you read the sources I referenced.
    – Double AA
    Mar 7, 2016 at 14:46
  • @DoubleAA I did in fact read your linked material. It's not clear what your objection to fire being an Av Melacha is an objection to in the answer, which uses differing concepts that don't entirely mesh with each other. Fire is an Av Melacha because it is specifically listed in the Torah, and I was pointing out that it fits within the rubric of "human consumption," irrespective of other objections. I am not opining on the correctness of the answer provided. Mar 7, 2016 at 14:53

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