“It is affixed to the right hand doorpost of the room, or house, or gate, where it is obligatory (see below), in the top third of the doorpost and slanting inward. A blessing “Who hast commanded us to fix the mezuzah” is recited when affixing it. The earliest evidence for the fulfillment of the commandments of the mezuzah dates from the Second Temple period. A mezuzah parchment (6.5 cm. × 16 cm) has been found at Qumran (Cave 8) in which are written some sentences from Deuteronomy (10:12 – 11:21) but not from the Shema (Discoveries in the Judean Desert of Jordan (1962), 158-61). The Samaritans make their mezuzot out of large stones and attach them to the lintel of the main door of their houses or place them near the doorway. They carve on them the Ten Commandments or the ”ten categories by which the world was created.” Sometimes they use abbreviations and initial letters of the ten or single verses in praise of God. Mezuzah stones of this sort are found in Israel dating from the early Arab and perhaps even Byzantine era. The Karaites do not make the mezuzah obligatory. Nevertheless, the mezuzot that they do attach are made of a tablet of blank plate in the form of the two tablets of the law but without writing on them and they fix them to the doorways of their public buildings and sometimes to their dwelling places.”
“In the Middle Ages the custom obtained of making kabbalistic additions, usually the names of angels, as well as symbols (such as the magen david) to the text. The custom was vigorously opposed by Maimonides. He declared that those who did so “will have no share in the world to come.” With their “foolish hearts” “they turn a commandment” whose purpose is to emphasize the love of God “into an amulet” (Yad, Tefillin 5:4). Despite this, there is one clear reference in the Talmud to the efficacy of the mezuzah as an amulet, though from the context it need not be regarded as doctrine. In return for a material gift sent by Ardavan to Rav, the latter sent him a mezuzah, and in answer to his surprised query replied that it would “guard him” (TJ, Pe’ah 1:1, 15d; Gen. R. 35:3). To a similar context belongs the story of the explanation of the mezuzah given by Onkelos the proselyte to the Roman soldiers who came to arrest him: “In the case of the Holy One, blessed be He, His servants dwell within, while He keeps guard on them from without” (Av. Zar. 11a).
Maimonides’ decisions prevailed, and the mezuzah today contains only the two biblical passages. However, at the bottom of the obverse side there is written the formula כוזו במוכסז כוזו, a cryptogram formed by substituting the next letter of the alphabet for the original, it thus being the equivalent of יהוה אלהינו יהוה (“the Lord, God, the Lord”). This is already mentioned by Asher b. Jehiel in the 13th century in his commentary to the Hilkhot Mezuzah of Alfasi (Romm-Vilna ed. p. 6b).”
“The mezuzah must be affixed to the entrance of every home and to the door of every living room of a house, thus ecxluding storerooms, stables, lavatories, and bathrooms, and must be inspected periodically (twice in seven years) to ensure that the writing is still readable. The custom has become widespread and almost universal at the present day to affix the mezuzah to the entrance to public buildings (including all government offices in Israel) and synagogues. There is no authority for this, unless the building or room is also used for residential purposes (Levi ibn Habib, Resp. no. 101), and the Midrash (Deut. R. 7:2) actually asks the rhetorical question, “Is then a mezuzah affixed to synagogues?” As the scriptural verse states, it is also to be affixed to “thy gates”. It is thus obligatory for the entrances to apartment houses. On the gates of the suburb Yemin Moshe in Jerusalem, which stand since their erection in 1860, the mezuzot are still to be seen. After the Six-Day War mezuzot were affixed to the gates of the Old City of Jerusalem. In the responsa Sha’ali Ziyyon of D. Eliezrov (1962. pt. 2, nos. 9-10), who served as rabbi to the Jewish political prisoners at Latrun during the British Mandate, there are two responsa from him and Rabbi Ouziel, Sephardi chief rabbi of Israel, as to whether mezuzot were obligatory for the rooms and cells of the camp.”
“In the Diaspora the mezuzot must be affixed after the householder has resided in the home for 30 days; in Israel, immediately on occupation. If the house is sold or let to a Jew the previous occupier must leave the mezuzah. It is customary, among the pious, on entering or leaving to kiss the mezuzah or touch it and kiss the fingers (Maharil, based on the passage from Av. Zar. 11a quoted above).”
“The Talmud enumerates the mezuzah as one of the seven precepts with which God surrounded Israel because of His love for them. Of the same seven (the zizit being regarded as four) R. Eliezer b. Jacob stated, “Whosoever has the tefillin on his head, the tefillin on his arm, the zizit on his garment, and the mezuzah on his doorpost is fortified against sinning” (Men. 43b). The mezuzah is one of the most widely observed ceremonial commandments of Judaism. In modern times the practice developed of wearing a mezuzah around the neck as a charm. Some of the cases in which the mezuzah is enclosed are choice examples of Jewish art, and the artistic mezuzah case has been developed to a considerable extent in modern Israel.”
Encyclopaedia Judaica (2007) XIV, 156-157
The old town of Lemberg/Lwów on the map of 1844 from the Ryszard Hubisz collection (the full map [8,3 MB] is here). To the north of the main square is located the 13th-century Armenian quarter, to the south the Jewish quarter, first mentioned in 1387. The core of the medieval Jewish quarter was the Neue Judengasse; it was later continued to the west along the Servengasse and Kapitelgasse. At the time of the Second Republic of Poland the whole street was named Bóimów after the chapel built by the Transylvanian Hungarian György Boim in the 16th century (about which we will write later). Today the street is called Староєврейська, Old Jewish street. On the map it is clearly shown that the courtyards of the houses within each block communicated with each other, as it is usual in old Jewish neighborhoods. The Jews were deported in 1941, and the 15th-century Golden Rose synagogue at the eastern end of the street destroyed. However, the doorposts of many houses still conserve the trace of the mezuzah. On the following map we have indicated with an oblique line the traces discovered by us, and with dots some other representative details of the houses concerned.