The gemara in Menachot (32b) states that there is a Halakha Le-Moshe Mi-Sinai requiring sirtut for a mezuza, but not for tefilin. In general, sirtut refers to lines or grooves that are etched into the parchment to facilitate the straight and un-crooked writing of the mezuza. However, several halakhot indicate that the practice of sirtut may constitute more than simply a technical device to assist neat writing.
Chief among these indications is a gemara in Gittin (6b)that requires sirtut for 3 or 4 words from Tanakh that are written in ANY context. Why does the gemara in Menachot (32b) attribute the sirtut requirement for mezuza to Halakha Le-Moshe Mi-Sinai,while the gemara in Gittin assumes it applies to any 3-4 words of Tanakh? How could Tefillin NOT require sirtut if ANY 3-4 words require sirtut? Finally, the gemara in Megilla derives sirtut for Megillat Esther from a comparison to Mezuza (some claim a comparison to a sefer Torah). Why does the gemara introduce an external comparison to derive sirtut for Megilla when ANY 3-4 words require sirtut according to the gemara in Gittin?
Evidently, the gemara in Gittin deduces a BASIC requirement of sirtut for ANY 3-4 words to ensure neat penmanship. As Rabbeinu Tam comments, for this purpose, a one line groove at the top of the page is sufficient. Some disagree and require lines along the two vertical margins, and some even demand an additional boundary toward the bottom of the page; regardless, neat writing can be assured with basic boundaries. This basic sirtut does not require a source. However, the more comprehensive sirtut – engraving EACH AND EVERY LINE of a mezuza, Megillat Esther, and possibly a sefer Torah – is more than just a technical manner of improving writing and requires sources and gezeira shaveh. What is the function of this comprehensive “every-line” sirtut?
One approach suggests that sirtut may be necessary to upgrade the text from a fragment of text to a sefer (book). The gemara in Megilla notes that Megillat Esther possesses a hybrid identity. It is referred to as a “sefer,” a formal book (Megillat Esther 9:32), and is also designated as an iggeret, a letter (9:29). The gemara concludes that certain parts of the Megilla’s construction should be formalized like a book, while others can remain informal like a letter. The Ramban comments that ONE aspect that formalizes the Megilla as a sefer is the line-by-line sirtut. In other words, according to the Rambam, the linear sirtut converts the text from a document into a book.
Similar sentiments stem from a comment of Rashi in Sota (17b), which similarly disqualifies a sota text written without sirtut because it fails the “sefer” test. When describing the ceremony of writing and then erasing a sota text, the Torah employs the same term of “sefer” (Bamidbar 5:23). According to Rashi, this formalizes the text of sota, and ONE requirement of this formalization is the line-by-line sirtut.
This may also explain the absence of sirtut from two objects that would logically require sirtut. First, several Rishonim (chief among them Tosafot) maintain that a sefer Torah does not require line-by-line sirtut, although it obviously requires the outline sirtut, similar to any 3-4 words of Tanakh. One way of assessing this riddle is to assume that sirtut upgrades a text into a sefer. In order to formalize fragments of Torah into actual books, line-by-line sirtut is required. Such is the case with mezuza, sota texts, and Megillat Esther. A complete Sefer Torah, however, is the PARAGDIM of a sefer and does not require the sirtut upgrade to confer that status.
The exception of tefillin may be similarly understood. The aforementioned gemara in Menachot attributes the difference between mezuza, which requires a sirtut, to tefillin, which does not, to a Halakha Le-Moshe Mi-Sinai. It is possible that a mezuza requires the halakhic status of a “sefer” and that status must be finalized through sirtut. Tefillin texts – as they are encased in housing and covered, are not considered a sefer, but rather text fragments incorporated into something larger. Absent this status of sefer, they do not require sirtut. This, in fact, may be the opinion of the Rambam, who asserts that tefillin do not require sirtut because the parasha texts are concealed, “mechupin” (Hilkhot Tefillin 1:12). He may have been referring to the fact that the enclosing of these texts within boxes of tefillin eliminates their status as sefer and thereby exempts them from sirtut.
A different approach to line-by-line sirtut may emerge from an interesting comment of one of the Geonim. Several later Rishonim cite the earlier Gaon Rabbenu Matatya, who claimed that while engraving the sirtut, the author must have intentions to convey requisite kedusha to the page, kavana li-shma. Although the Tur rules against this position, it highlights an interesting option – perhaps the line-by-line sirtut is part of the formal writing process of the mezuza and certain select documents. The process of writing these documents entails not merely applying texts but rather carving or outlining margins and adding text. Just as the actual writing must be performed li-shma, with proper intentions, to instill kedusha, the sirtut must be performed li-shma as well, since it is PART of that writing process. Text within discernible boundaries is superior text and certain halakhic texts require this higher form of writing.
This concept would also explain a very interesting query of R. Akiva Eiger (1:50) about adding sirtut AFTER the actual text has been written. Presumably, if the sirtut merely confers the independent “sefer” factor, it may be added AFTER the text has been applied. However, if the creation of line-by-line margins is PART of the halakhic act of writing certain texts, it may not be inserted AFTER the text has been written.
Finally, this view of sirtut may also explain the absence of this requirement for tefillin texts. As the Rambam notes, the tefillin texts are inserted into the houses of tefillin. Their ultimate kedusha only emerges at a later stage, well after the WRITING. In contrast, mezuza and sefer Torah receive their final kedusha from the act of writing the text. Hence, this act of writing must be a DELUXE act, which includes adding sirtut. Since the ultimate kedusha of tefillin is delayed until they are inserted into the houses, the act of writing can be accomplished without the added dimension of sirtut. In fact, the Rambam cites the sirtut rules in the same halakha (Tefillin 1:12) that he cites several other laws governing the act of writing. Thus, it appears as if sirtut- when necessary – is an element of the act of writing.