The Gemara in Baba Basra 119b relays the following conversation that took place in this week’s parshah: Moshe Rabbeinu was teaching the halachos of yibum when the daughters of Tzelaphchad approached him with the following question: Our father died in the midbar and did not have any sons. Why then is our mother not required to fulfill the obligation of yibum? And if the fact that he had daughters is the reason that she is not obligated to fulfill this requirement, why then can we (his daughters) not receive an inheritance – just like sons would?
The Gemara in Shabbos 96b says in the name of Rabbi Akiva that Tzelaphchad was the individual who was mekoshesh eitzim (the gatherer of wood) in the midbar on Shabbos. This act of Shabbos desecration was the reason he was put to death.
The Chasam Sofer (Teshuvos 6, likutim 56) was asked the following question: The Mordechai’s opinion is that a mummar’s wife does not fall into the category of yibum since the deceased husband is not worthy of having his name upheld. How then could the daughters of Tzelaphchad have asked that their mother be required to fulfill yibum when their father was, in Rabbi Akiva’s view, a mummar due to having been the mekoshesh? Why didn’t Moshe Rabbeinu simply answer that their father was considered a mummar, thus negating their mother’s requirement to fulfill yibum?
One answer that the Chasam Sofer offers is that the halacha of the Mordechai only applies when one dies while still a mummar, for only then is he not worthy of retaining his name. However, Tzelaphchad did teshuvah before he died and therefore his wife could fall to yibum even according to the Mordechai. We see this from the fact that the Torah listed with him all of his ancestors – who were all tzaddikim.
Another answer that the Chasam Sofer suggests is that the Mordechai’s halacha does not apply to a mummar unless he leaves the religion and joins a different one. Only such a person is not worthy of having his name upheld. But a mummar who does not leave the religion to join another one, even if he desecrates Shabbos or does avodah zarah, is still worthy of having his name upheld. Thus, even the Mordechai would agree that his wife would fall to yibum; hence Tzelaphchad’s wife was able to fall to yibum.
The Chasam Sofer also points out that the question is based on a premise that is not necessarily true. He says that it is not clear whether the mekoshesh acted in public or in private when desecrating Shabbos. Had he acted in private, he does not attain the status of a mummar. There is a machlokes as to which melachah the mekoshesh transgressed; one says he carried four amos in reshus ha’rabim, another says he cut off the branches, and a third says he was making piles. According to the opinions that he cut off the branches or that he made piles, there is no indication that he acted in public. Therefore he would not be considered a mummer and his wife could fall to yibum.
On face value it seems that the Chasam Sofer forgot a Tosafos in Sanhedrin (78b d”h lo). There Tosafos says that Moshe Rabbeinu reasoned that the mekoshesh should deserve death by stoning, since a mechalel Shabbos in public is likened to one who does avodah zarah (who is stoned). The Chasam Sofer’s father-in-law, Rabbi Akiva Eiger, understands the Tosafos to mean that he acted in public. We see this from his question on Tosafos. He asks that since according to Tosafos a mechalel Shabbos can be killed (just as one who does avodah zarah, since a mechalel Shabbos is likened to a practitioner of avodah zarah), how do we then know what Hashem’s answer to Moshe was? Perhaps Hashem agreed with Moshe that the mekoshesh should be stoned only because he acted in public, thereby likening him to one who did avodah zarah. However, one who desecrates Shabbos in private but who is not compared to one who does avodah zarah would receive death by strangulation (the form of death given when the Torah does not specify which form of death).