Keriat HaTorah, for the most part, is a rabbinical obligation. The one exception generally noted is the reading of the Parsha of Amalek before Purim (according to many explanations of the Rosh in Masechet Berachot). However, many Rishonim, such as Rashba (Berachot 13a), have included another reading as a biblical obligation: Parshat Parah, which appears originally in Parshat Chukat and is traditionally read right after Purim. This notion is also quoted in Shulchan Aruch (Orach Chaim 146 and 685).
This is a somewhat puzzling assertion, as it is unclear where exactly in the Torah we find a commandment to read Parshat Parah (see Magen Avraham, O.C. 685, and Aruch HaShulchan 685:7). Such a gaping hole has led some authorities (such as the Vilna Gaon) to maintain that the entire reference is actually a scribal error, and the reference was not to Parshat Parah but to “Parshat Purim,” another name for the Parsha of Amalek that shares Parshat Parah’s initials. Others, hesitant to label as error a statement found in numerous Rishonim, offer innovative theories to explain the source. (See, for example, Meshekh Chokhmah and Torat Moshe, as well as Responsa Divrei Yatziv, Orach Chaim 288).
One theory that is put forward (see Artzot HaChaim of the Malbim, Hilchot Tzitzit, and Responsa Arugat HaBosem, Orach Chaim 205) concerns those select concepts and commandments that the Torah has distinguished with an imperative of “remember” (the Zechirot). Authorities differ as to the precise count of these precepts, but they include prominently such concepts as Amalek, Shabbat, and the exodus from Egypt. And indeed these three find Halachic expression: we remember Amalek through the special Keriat HaTorah, Shabbat through Kiddush on Friday night, and the exodus through its mention twice a day in the third paragraph of Keriat Shema.
However, one concept that appears to deserve inclusion seems to lack Halachic representation. Regarding the Cheit HaEigel, the Torah commands: “Remember, do not forget, how you angered Hashem, your God, in the desert” (Devarim 9:7). If so, why does no ritual or reading commemorate the incident of the golden calf? Should there not be an implementation in Jewish practice of this obligation?
Therefore, it is suggested, perhaps this indicates a source for a biblical obligation of Parshat Parah. Chazal perceived a linkage between the Mitzvah of Parah Adumah and the sin of the golden calf. As Rashi says, “Let the mother come and clean up the soiling of the child.” The adult cow symbolizes the parent, and in atoning for Cheit HaEigel, it is “cleaning up” the mess of the calf.
Within that understanding, it may be posited that the sin of the calf is indeed commemorated, albeit in an indirect manner. Rather than directly evoke the disgraceful episode of the golden calf, we chose a less embarrassing path, reading about the commandment that atones and not about the transgression that incurred guilt.
Such a reading would reflect back on the very nature of the obligation of remembering the calf. The focus is not on the sin, but rather on the path back from impurity. The Torah wishes to impress upon the psyche that even in the aftermath of egregious moral failing, the route of return remains open.
However, there were those who assumed a different theme in this commandment of remembering. Some suggest that we are told to constantly recall the instance of the calf as a cautionary measure. At the time of the sin, the Jewish people were on an extremely high level of spirituality, so close to the occasion of the giving of the Torah. At such a time, one may believe himself invulnerable to temptation or moral error, protected by a bubble of holiness. The incident of the calf must always be remembered to warn that no one is protected in that manner, and that descent to sin can happen whenever inadequate care is taken.
If that is the theme, then, it would seem that using the Parah Adumah as a reminder would be an ineffective method. It may represent atonement, but the message of spiritual vigilance would be lacking.
However, it might be suggested that even this motif is present in the Parah Adumah. We are well aware of the central paradox of this commandment. At the same moment that it confers purity upon the impure, it incurs impurity on to the purifiers. From a straight logical perspective, this is confounding: is the Red Heifer a vehicle of purity or of impurity?
It might be suggested that this is precisely where the warning of Parah Adumah lies. At times, one may feel that he is on such a high level as to be invulnerable from stumbling. This could have been the mentality of the Jews at the time of the golden calf; at such a point in history, how could they sin? We are bidden to constantly remember this incident in order to remind us that no one is absolved from the responsibility of personal vigilance.
In its own way, the Parah Adumah makes this point as well. If one is involved in a religious activity, in a rite of purification, it might be assumed that one is insulated from any spiritual failing. Yet we find that even this activity contains the elements of impurity. The message is clear: no context or activity is a spiritual guarantee; it is only through constant, careful, self-awareness that one can ensure that his behavior is actually a true expression of the Ratzon Hashem.