Tithes in Judaism
The tithe is specifically mentioned in the Books of Leviticus, Numbers and Deuteronomy. The tithe system was organized in a seven-year cycle, the seventh-year corresponding to the Shemittah-cycle in which year tithes were broken-off, and in every third and sixth-year of this cycle the Second tithe replaced with the Poor man's tithe. These tithes were in reality more like taxes for the people of Israel and were mandatory, not optional giving. This tithe was distributed locally "within thy gates" (Deuteronomy 14:28) to support the Levites and assist the poor. Every year, Bikkurim, Terumah, Ma'aser Rishon and Terumat Ma'aser were separated from the grain, wine and oil (Deuteronomy 14:22). Initially, the commandment to separate tithes from one's produce only applied when the entire nation of Israel had settled in the Land of Israel. The Returnees from the Babylonian exile who had resettled the country were a Jewish minority, and who, although they were not obligated to tithe their produce, put themselves under a voluntary bind to do so, and which practice became obligatory upon all.
The first obligation that was incumbent upon an Israelite or Jew was to separate from his harvested grain (wheat, barley, spelt, etc.), wine (including unpressed grapes) and oil (including unpressed olives) the one-fiftieth portion of these products (or one-fortieth, if he were a man of generosity; and one-sixtieth if he were stingy) and to give the same to a Kohen, who, in turn, would eat such fruits in a state of ritual cleanness, in accordance with a biblical command, "...and let him not eat of the holy things, until he bathes his flesh in water. And when the sun goes down, he will be clean, and shall afterward eat of the holy things because it is his food" (Leviticus 22:6). This obligation was contingent upon the fact that such fruits grew in the Land of Israel. Later, the Rabbis made it an obligation to do the same for all fruits and vegetables grown in the Land of Israel, and not only to such fruits as grain, grapes and olives. With the destruction of the Temple and the cessation of ritual purity, the obligation to separate the Terumah continued unabated, although it was no longer given to a priest of Aaron's lineage, since bodily defilement was now pervasive. The general practice after the Temple's destruction was to separate the Terumah from all fruits and vegetables by removing even the slightest portion thereof, and to immediately discard it by burial or some other means of disposal (since it can no longer be eaten in the current state of ritual uncleanness, and those doing so would make themselves liable to extirpation).
The first tithe is giving of one tenth of the remaining agricultural produce (after removing from the produce the standard Terumah) to the Levite (or Aaronic priests). Historically, during the First Temple period, the first tithe was given to the Levites. Approximately at the beginning of the Second Temple construction, Ezra and his Beth din implemented its giving to the kohanim.
The Levites, also known as the Tribe of Levi, were descendants of Levi. They were assistants to the Aaronic priests (who were the children of Aaron and, therefore, a subset of the Tribe of Levi) and did not own or inherit a territorial patrimony (Numbers 18:21-28). Their function in society was that of temple functionaries, teachers and trusted civil servants who supervised the weights and scales and witnessed agreements. The goods donated from the other Israeli tribes were their source of sustenance. They received from "all Israel" a tithe of food or livestock for support, and in turn would set aside a tenth portion of that tithe (known as the Terumat hamaaser) for the Aaronic priests.
Unlike other offerings which were restricted to consumption within the tabernacle, the second tithe could be consumed anywhere within the Walls of Jerusalem. On years one, two, four and five of the Shemittah-cycle, God commanded the Children of Israel to take a second tithe that was to be brought to the place of the Temple (Deuteronomy 14:23). The owner of the produce was to separate and bring 1/10 of his finished produce to the Old City of Jerusalem, after separating Terumah and the first tithe, but if the family lived too far from Jerusalem, the tithe could be redeemed upon coins (Deuteronomy 14:24-25). Then, the Bible required the owner of the redeemed coins to spend the tithe "to buy whatever you like: cattle, sheep, wine or other fermented drink, or anything you wish" (Deuteronomy 14:26). Implicit in the commandment was an obligation to spend the coins on items meant for human consumption.
Poor man's tithe
In years three and six of the Shemittah-cycle the Israelites set aside the (second) tithe instead as the poor tithe, and it was given to the strangers, orphans, and widows.
Terumat hamaaser was given by the Levite to the Kohen, and was one-tenth of what the Levite had received of the First-tithe. It is alluded to in the Hebrew Bible under the words, "a tithe (tenth) of the tithe" (Numbers 18:26). It, too, was considered Terumah, and was eaten by priests in a state of ritual cleanness. Today, the Terumat maaser is discarded because of general uncleanness, just as the Terumah is now discarded.
Demai (Mishnaic Hebrew: דמאי) is a Halakhic term meaning "dubious," referring to agricultural produce, the owner of which was not trusted with regard to the correct separation of the tithes assigned to the Levites, although the terumah (the part designated unto priests) was believed to have been separated from such fruits. In such "dubious" cases, all that was necessary was to separate the one-tenth portion due to the priests from the First Tithe given to the Levites, being the 1/100th part of the whole. The Second Tithe is also removed (redeemed) from the fruit in such cases of doubt.
Places that require tithing
The criterion for determining what places require the tithing of produce is any place within the country that was held by the Returnees from the Babylonian exile, as defined in the "Baraita of the Boundaries" of the Land of Israel; although today the land might be held by a different entity, or else worked by non-Jews, produce grown in those places would still require the separation of tithes when they come into the hand of an Israelite or Jew.
Tithes are broken-off during the Sabbatical year (such as when the ground lies fallow), during which year, all fruits, grains and vegetables that are grown of themselves in that year are considered free and ownerless property. For example, whatever lands were held by those returning from the Babylonian exile at the time of Ezra are forbidden to be ploughed and sown by any Jew during the Seventh year, and even if gentiles were to plough such land and sow it, the produce would be forbidden unto Jews to eat. On the other hand, the extension of such lands held by the people of Israel who departed Egypt and who entered the Land of Canaan under their leader, Joshua, are forbidden to be ploughed by any Jew during the Seventh year, but if gentiles had ploughed such land and sown it, the produce is permitted to be eaten by a Jew. If on a regular week-year, fruits and grains and vegetables, if grown by an Israelite in these places, would require tithing.
- Maimonides, Mishne Torah (Hil. Terumot 1:26)
- In accordance with Midrash Rabba, Ruth Rabba 4:7, "Three things did the terrestrial Court enact and the celestial Court agreed with them, which are these: To greet a person by employing [God's] Name, [to give juridical legitimacy to] the scroll of Esther, and [to require the separation of] tithes. Tithes, from whence [did they base its legitimacy]? For Rabbi Berakhia said in the name of [Rabbi] Krispa, 'By the neglect of heave-offerings and tithes they were exiled.' Shimon bar Abba said in Rabbi Yohanan's name that since they were exiled they were exempt [from the obligation of tithing], but they, of their own volition, put themselves under the obligation, etc."
- Mordecai Yehudah Leib Sachs and Yosef Qafih (ed), Perush Shishah Sidrei Mishnah (A Commentary on the Six Orders of the Mishnah), s.v. Tractate Ma'aser Rishon, appended at the end of the book: The Six Orders of the Mishnah: with the Commentaries of the Rishonim, vol. 2, pub. El ha-Meqorot: Jerusalem 1955, p. 6
- Maimonides, Mishne Torah (Hil. Terumot 1:1)
- Maimonides, Mishne Torah (Hil. Terumot 2:6)
- The Talmud Adin Steinsaltz 1992 "Yet if a priest has first tithe in his possession, he need not give it to a Levite. Ezra penalized the Levites of his generation because they did not return to Eretz Israel with him, and he decreed that first tithe should be given to ..."
- Restoration: Old Testament, Jewish, and Christian perspectives p329 James M. Scott - 2001 "One says that the Levites were punished because they did not come up to the Land of Israel during Ezra's days. The other says that the first tithe was given to the priests, so that they would have food when they were in a state of ..."
- Mordecai Yehudah Leib Sachs (ed), Perush Shishah Sidrei Mishnah (A Commentary on the Six Orders of the Mishnah), vol. 2, appended at the end of the book: The Six Orders of the Mishnah: with the Commentaries of the Rishonim, p. 3b , pub. El ha-Meqorot: Jerusalem 1955; Mishnah - with Maimonides' Commentary (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Demai 1:1, p. 79.
- Mishnah - with Maimonides' Commentary (ed. Yosef Qafih), vol. 1, Mossad Harav Kook: Jerusalem 1963, s.v. Demai 1:1, p. 79.
- Ha-Radbaz (Commentary of Rabbi David ben Zimra), on Maimonides' Mishne Torah (Hil. Terumot 1:8), who cites the Jerusalem Talmud, Tractate Shevi'it, ch. 6.
- Maimonides, Mishne Torah (Hil. Terumot 1:10)
- Mordecai Yehudah Leib Sachs and Yosef Qafih (ed), Perush Shishah Sidrei Mishnah (A Commentary on the Six Orders of the Mishnah), s.v. Tractate Shevi'it, ch. 6, appended at the end of the book: The Six Orders of the Mishnah: with the Commentaries of the Rishonim, vol. 1, pub. El ha-Meqorot: Jerusalem 1955, p. 49 
- Mordecai Yehudah Leib Sachs and Yosef Qafih (ed), Perush Shishah Sidrei Mishnah (A Commentary on the Six Orders of the Mishnah), s.v. Tractate Shevi'it, ch. 6, appended at the end of the book: The Six Orders of the Mishnah: with the Commentaries of the Rishonim, vol. 1, pub. El ha-Meqorot: Jerusalem 1955, p. 49 ; Maimonides, Mishne Torah (Hil. Terumot 1:7)
- "Tzedaka and Maaser Kesafim" (PDF). dafdigest.org. Chicago Center for Torah and Chesed. May 23, 2006. Number 449. Archived from the original (PDF) on May 26, 2011. Retrieved February 3, 2015.