The conclusion of parshat Tezaveh delineates the laws and role of the mizbeach ha-ketoret. Many of the commentators (Ramban, Ibn Ezra, Seforno, Meshech Chochmah, Haamek Davar on Shemot 30:1) were puzzled by the fact that the Torah did not previously incorporate this crucial component in its otherwise comprehensive chronicle of the mishkan in parshat Terumah. Why does the Torah isolate the mizbeach ha-ketoret both from its discussion of the other mizbeach (ha-olah), and from its presentation of the shulchan and menorah that are also situated in the heikhal? Moreover, why was it necessary to delay the introduction of the mizbeach ha-ketoret until after the Torah reviews the miluim process and articulates the purpose of the entire mishkan structure- "ve-shachanti betoch benei yisrael ve-hayiti lahem Leilokim..." (29:45-46)? Perhaps a better understanding of the role and character of the mizbeach ha-ketoret will illuminate the Torah's decision to set it apart from the rest of the mishkan structure.
The relationship between the mizbeach ha-ketoret and the other mishkan structures is complex and dialectical. On the one hand, there is some evidence that the mizbeach ha-ketoret does not play as vital a role as the other components. The gemara (Zevachim 59a) concludes that the ketoret could continue to be offered on that venue even if the mizbeach was uprooted. The Meshech Chochmah notes that this ruling is implicit in a verse in Melachim (1:9) and he posits that precisely because it is not indispensable, it was omitted from the Torah's initial presentation. Moreover, there may be some significance to the fact that the mizbeach ha-ketoret's placement in the heichal is more distant from the aron and kodesh kodashim than either the shulchan or menorah.
At the same time, there are ample indications that mizbeach ha-ketoret achieves a more elevated role and stature than any of the other structures. Unlike the copper mizbeach in the azarah, the mizbeach ha-ketoret was constructed of refined, pure gold. The gemara (Zevachim 27a) establishes that while the copper mizbeach was adjudged to be just an extension of the floor of the azarah ("rizpah"), the golden mizbeach of the heichal achieved the status of a "keli sharet", guaranteeing the permanence of its sanctity. While the copper mizbeach is designated as "kodesh kodoshim" (29:37), the golden mizbeach attains the higher status of "kodesh kodoshim hu la-Hashem" (30:10) in the final verse of the parshah. The Meshech Chochmah and Netziv invoke this elevated status to justify why it is that the golden mizbeach has the capacity to sanctify even objects that are not fit to be offered while the copper mizbeach can only affect appropriate sacrifices.
The mizbeach ha-ketoret also appears to surpass the menorah and shulchan in some respects. Rav Hirsch notes that while the more proximate menorah and shulchan are described as being outside the confines of the kodesh ha-kodoshim ("mi-chutz la-parochet"- 26:35), the more distant golden mizbeach is actually depicted as being located in its presence ("lifnei ha-parochet, lifnei ha-kapporet"- 30:6)! Furthermore, only the more distant mizbeach ha-ketoret directly faces the aron!
The fact that the mizbeach ha-ketoret defies classification partially explains its isolated treatment. However, we can further appreciate the Torah's decision to extricate the presentation of the mizbeach ha-ketoret from the larger mishkan structure according to those commentators (Rav Hirsch, Netziv etc.) who perceive the mizbeach ha-ketoret as representing a mediating or integrating force that provides an ideal balance between spiritual (menorah) and physical (shulchan) dimensions of avodat Hashem. The physical structure of the heichal, in which the mizbeach is between but removed from both components, dramatizes this role. It was necessary to initially withhold discussion of the mediating principle so that each manifestation of Torah life could find full expression. The mizbeach ha-ketoret had to be separate and subsequent to allow for the independence and integrity of each vital component. This would ensure that the mediating function would not constitute a dilution or compromise of each model of spirituality, but an ideal enhancement of each. It would also establish that these models represent the core of avodat Hashem, while the contribution of the mizbeach ha-ketoret constitutes a refinement and enhancement.
This also may explain the complex character of the mizbeach ha-ketoret. It may not be indispensable and does not stand as an independent structure. The sacrifice of the ketoret itself is supposed to be integrated into the menorah process. As an isolated component, the mizbeach ha-ketoret is more distant from the aron than either the shulchan or menorah. Otherwise, it would not represent the integration and balance of the two but their dilution and compromise. However, once the shulchan and menorah have been independently established, it is the integrating function of the mizbeach ha-zahav that becomes the ultimate symbol of maximal religious aspiration. Thus, this mizbeach is more distant from the aron, but, more importantly, it draws its guidelines and inspiration in a direct line. Though it is further removed from the kodesh ha-kodoshim than its two heichal counterparts, it is the ideal mizbeach ha-ketoret exclusively that is depicted as "lifnei ha-parochet". A mizbeach ha-ketoret that functions in this nuanced way is able to exert greater influence than its mizbeach ha-olah counterpart. It is "kodesh kodashim hu la-Hashem" and therefore its capacity to transform and sanctify extends even to objects normally unfit for the altar.
The Torah formulates a prohibition against sacrificing unauthorized ketoret or other inappropriate substances on the mizbeach ha-ketoret (ketoret zarah- 30: 9) that does not have a parallel in any of the other structures. It is possible that extra scrutiny in following strict guidelines and in attaining the proper balance is required because the very function of this mizbeach is to integrate and regulate divergent emphases in avodat Hashem.
The Torah concludes its presentation of the mizbeach ha-ketoret (30:10) by noting the link to the avodah on Yom Kippur. It is striking that the yearly kapparah for tumat mikdash and kodashim is accomplished by the sprinkling of the sacrificial blood specifically on this mizbeach, although it is otherwise reserved only for the ketoret. The ideal and ambitious role that the mizbeach ha-ketoret plays in the mikdash structure justifies this choice. [The link to Yom Kippur itself is hardly coincidental. In some respects there is a parallel between the perspective that Yom Kippur provides in the world of the moadim and to the concept of the sanctity of time and the function of mizbeach ha-zahav in the framework of the mikdash. This might also explain why only the blood sprinkling of Yom Kippur is cited in this context, despite the fact that the blood of other parim ha-nisrafin are also sprinkled on this alter.] The verse concludes appropriately by affirming mizbeach ha-ketoret's central role and singular impact: "kodesh kodashim hu la-Hashem"