The mishna in Pesachim (85b) describes the exact boundaries of Yerushalayim regarding the location in which it is permissible to eat the korban Pesach. The mishna states that the 'top-width' of the walls (ancient walls were built thick and one could walk or even live in the width-space of the walls; remember Rachav the prostitute who actually lived IN the wall), and windows (similarly thick windows built into the walls) are considered part of Yerushalayim. The gemara, however, takes issue with this mishna based upon a statement of Rav regarding the kedusha of the azara (the courtyard of the Beit Ha-mikdash within which one was allowed to eat korbanot kodshei kodashim). He declared that the rooftops and lofts adjacent to the azara were not installed with kedushat Beit Ha-mikdash - and one could not eat a korban in these locations. Presumably, any area which was not at 'ground level' was not installed with kedusha. If so, the top of a wall (its width) should be no different from adjacent lofts and rooftops (each not being ground level) and should not contain kedusha. The mishna seems to contradict Rav's explicit ruling.
Based upon this question, the gemara adjusts the statement of the mishna regarding 'walls and windows'. What the mishna intended was really a very unique type of wall known as a 'bar shura'. This was, in truth, a small 'mini-wall' built within the taller outer wall. In many cases the top of this wall was at the same level of the actual ground of the azara or of Yerushalayim, as the case may be. The ground of the Yerushalayim, not being flat had ascents and descents. Hypothetically, if this mini-wall of Yerushalayim were built in a low-level location it would then be situated at the very same level as an acclivity in another area of Yerushalayim. Hence, it would be considered 'ground level' which contains kedushat Yerushalayim. It cannot be compared to roofs and lofts and would not contain the respective kedusha.
The gemara contrasted the mishna's statement about the boundaries of Yerushalayim to Rav's about the boundaries of the azara. This facile comparison forced the gemara to modify the mishna's mapping.
This alteration of the gemara is largely ignored by the Rambam. In two instances - Hilkhot Ma'aser Sheni 2:16, Hilkhot Ma'aseh Ha-korbanot 10:5 - he discusses the boundaries of Yerushalayim and in each case he cites the mishna literally - that the top-width of the walls as well as windows are considered part of Yerushalayim. In no instance does he clarify or elaborate based on the gemara's modifications. In no instance does he remark that walls only refer to bar shura - small mini-walls which conceivably are considered ground level.
In solving the Rambam, the possibility presents itself to distinguish between the kedusha of Yerushalayim and that of the azara. Possibly, Rav's statement excluding rooftops and lofts was made regarding the AZARA, while the mishna in Pesachim, which includes the top-width of walls, was stated in reference to YERUSHALAYIM. As these two kedushot are different, their lines of demarcation are different. Indeed, the gemara did not differentiate between the two and therefore posed its question, and arrived at its modification. The Rambam, however, might have chosen this distinction which the gemara ignored. This approach, though feasible from a hypothetical standpoint, cannot solve the Rambam. In Hilkhot Beit Ha-Bechira 6:9, while discussing the boundaries of the azara, the Rambam includes the top-width of walls without adding that this refers only to the special bar shura walls. Evidently ALL WALLS - those of the azara as well as those of Yerushalayim contain kedusha even though they are not ground level.
This approach, however, might explain the position of the Ra'avad. When the Rambam includes walls within the boundaries of YERUSHALAYIM (Hilkhot Ma'aser Sheni and Ma'aseh Ha-korbanot) the Ra'avad does not comment. Evidently he accepts the Rambam's blanket inclusion of all walls - even those which aren't ground level. However, in Hilkhot Beit Ha-bechira, when the Rambam includes all WALLS within kedushat azara the Ra'avad disagrees. Being that these walls were not ground level they do not contain kedushat azara. The only walls which contain this kedusha, the Ra'avad insists, were bar shura, which, because of the different gradients, were ground level. Though, the Rambam maintains the parallel between Yerushalayim and the azara, the Ra'avad differentiates between them. All of the walls surrounding Yerushalayim contain its kedusha, whereas only 'ground-level' walls of the azara contain its kedusha. Evidently, according to the Ra'avad, the kedusha of Yerushalayim and that of the azara are disparate.
As stated earlier, the gemara assumed absolute equality between Yerushalayim and the azara. Rav's statement excluding the rooftops and lofts was unquestionably applied to Yerushalayim as well. Rashi states this quite clearly in his comments to Pesachim (85b). The Yerushalmi in Pesachim however, cites a machloket regarding the rooftops of Yerushalayim. Evidently, according to the Yerushalmi as well, there is room to differentiate between Yerushalayim and the azara. The mishna's statements regarding the walls and windows of Yerushalayim does not necessarily apply to the walls and windows of the azara. Alternatively, Rav's statement regarding the rooftops and lofts of the azara does not necessarily have validity regarding Yerushalayim. The two kedushot are manifestly different.
The Or Same'ach (Hilkhot Beit Ha-bechira 6:7) elaborates on the different textures of kedusha. The kedusha of the azara is one which, undoubtedly, stems from the general kedusha of the Beit Ha-mikdash. As such, at its root, it is a kedusha which inheres within a 'BAYIT' (house) and so is defined and delimited by the structural considerations of a house. Any area which is considered part of that house, necessarily contains kedusha. Any adjacent area which is not within the confines of the HOUSE is excluded from kedusha. For this reason Rav excludes the lofts and rooftops from kedushat azara; these are not regarded as the main living space of the house. Particularly in the case of the roof, as they aren't protected within the walls of the house, they can not be considered part of the dwelling. (The Or Same'ach does not focus upon this quality of protection but it seems reasonable given his overall thrust). Similarly, one expects that the tops of the walls might not be included within kedushat azara since they do not represent the primary dwelling area of a house. By contrast, the kedushat Yerushalayim is one which inheres within a CITY and its scope is defined by the parameters of a municipal area. For this reason the mishna in Pesachim asserted that windows and the top-width of a wall are included within kedushat Yerushalayim. Though they are not strictly within the confines of a house (they aren't enclosed by the walls of a house) they are, nonetheless, part of the city area. Similarly, one might suggest that according to the Ra'avad, the rooftops and lofts of Yerushalayim, in contrast to those of the azara do contain kedusha. Though they might not be considered part of a house they are considered part of a CITY, whose dimensions extend far beyond walls
The Or Same'ach suggested a fundamental distinction between the essence of kedushat azara and kedushat Yerushalayim. This would clarify the conflicting statements accepted by the Ra'avad regarding these distinct areas.
Quite possibly, the Or Same'ach's distinction, and particularly his definition of kedushat Yerushalayim as one which is 'urban', would help explain an intriguing halakha regarding Yerushalayim. The mishna in Shavu'ot (14a) describes the process by which kedushat Yerushalayim was conferred. Essentially the entire nation followed Beit Din, the melekh and the navi in circling Yerushalayim with two korban todot. Rashi (15a) comments that they circled the city from its outer periphery - from BEYOND the walls. The Rashba argues with Rashi and maintains that the walls were circled from WITHIN. According to Rashi's view, the result was be that an extra 'step' or 'footspace' outside the walls of the city were actually installed with kedusha. The Rashba does not accept this (partially based upon a gemara in Makot (19b)) and maintains that by circling INSIDE the walls, only the precise area of Yerushalayim was endowed, by the nation, with kedusha. Presumably, the Or Same'ach's definition of 'urban kedusha' might afford greater flexibility and accommodate Rashi's dimensions. Though the 'step' beyond the walls is not encompassed within the walls, they are certainly part of the overall 'municipal area' and hence are candidates for kedushat Yerushalayim.
1. Oftentimes, similar halakhot are compared by the gemara or by a commentator. Question whether this comparison is inarguable. Is it possible to distinguish between these similar but different halakhot?
2. Pay close attention to the manner in which the Rambam cites a halakha. Oftentimes he cites a mishna, but not the subsequent alteration of the gemara. This forces a different thrust to the sugya. Of course, the question of authority - can the Rambam reject a gemara - remains to be answered.
3. Similarly, inspect the method of the Ra'avad's responses to the Rambam. Is there consistency in the way he argues with the Rambam? Can we detect distinctions unique to the Ra'avad by studying the pattern of his responses?
The Or Same'ach's definition of kedushat Yerushalayim has philosophical ramifications as well. Unlike other cultures which situate their 'temples' and 'altars' outside the city, well beyond human habitat, Judaism centralizes its Beit Ha-mikdash (le-havdil) within the city of Yerushalayim - as the heart of that city, which in turn is the capital of the nation. It does not seek to sever religious life from the common, daily intercourse of 'civil life'. It does not view the common as that which is profane or unholy threatening to undermine the intensity of the holy experience. Rather, it sees within that experience an additional arena for integrating the entirety of the life cycle within the fabric of religious experience and Avodat Hashem.
May we all merit the rebuilding of the Beit Ha-mikdash and the return of all children of Zion to their united capital.