halacha - What portion of his income would a Jew following the sacrificial laws give?

Christians are often told that tithing is a practice established in the law of Moses, and may be expected to respect this as a baseline for giving.

But as I read through the Pentateuch, I see quite a few tithes and offerings. Some is for priests, some is for festivals. There are sin offerings and peace offerings. Surely this is more than the oft-attributed ten percent, no? I've some people reckon closer to 25 or thirty percent of an average Jew's salary, but without referencing specific offerings in scripture or working out any math.

So the question is, what are the tithes and offerings in the Pentateuch, and how much would they have cost an average Jew at the time, as a proportion of their income?

Answer

A farmer living in Israel in Temple times would have given as follows:

• Approximately 2% of his crops to the Kohen (priest); known as teruma.


• 10% of his remaining crops to the Levite; ma'aser which means "tithing." (The Levite would then tithe that -- i.e. ~1% of the original crop -- and give it to the Kohen.)


• 10% of what's still remaining; depending on the year (there's a cycle), this is either given to the poor, or consumed by the farmer himself in Jerusalem.


• First fruits (that's not that many, quantity-wise; it's more about the significance) to the Kohen, at the Temple.


• The growth from his vineyard's fourth year would have to be consumed (by the owner) in Jerusalem.


• A "corner" (of some size) of a grain field should be left for the poor; as should random dropped sheaves or the occasional forgotten bundle. Similar laws apply to vineyards. (Once again this one, as I understand it, isn't so much about the quantity as it is about behavior modification.)


• A small piece (~5%) of dough, when kneading, is given to the Kohen.

And from livestock (cows, sheep, goats):

• Firstborn cows, sheep, and goats are given to the Kohen. Firstborn donkeys necessitate a lamb given to the Kohen. At first glance it looks like a cow will have about ten calves over her lifetime, so this is approximately 10%, if you're keeping count.


• Of the remaining flock, 10% must be consumed in Jerusalem.


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  When slaughtering an ordinary animal not as a sacrifice, the jaws, foreleg, and chest are given to a Kohen.

  
  


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  One lamb/kid consumed by its owners for Passover offering, in Jerusalem. Though many people can go in on this, as long as each person gets two ounces or so of meat.

  
  


• Some extra offering when visiting for the holidays; but again, you can go in with others for this (or even "be a total parasite", as a teacher of mine explained).


• The occasional offerings for sin atonement, as needed (hopefully not).

Money:

• An annual half-shekel to cover the Temple's communal offerings.

So if Farmer Asher grew 100 bushels of wheat, he'd wind up with -- oh, let's say about 75 bushels with which he could do anything; plus 8 bushels that will either go to the poor, or Farmer Asher should eat himself in Jerusalem, depending on the year.

Today

Now Jacob promised G-d "all that you give to me I shall definitely tithe to you"; so for the non-agarian, non-Temple times, non-Israel dweller, the strongly normative and recommended practice (and while debated, we conclude it's not quite an obligation per se) is to give 10% of one's profits to charity. Giving up to 20% is considered meritorious; beyond that is not recommended as one risks putting themselves into poverty.