As we learned on yesterday’s daf (=page), only voluntary sacrifices whose meat is eaten by the owner of the offering can be purchased with money from redeemed ma’aser sheni (second tithes). Such money cannot be used to purchase obligatory sacrifices – even those whose meat is eaten by the owner – since obligatory sacrifices can only come from ordinary money and not from sanctified money.
The Mishnah on today’s daf searches for a source for this law. The passage that is suggested says that the korban Pesach – the Pascal sacrifice – must be brought from tzon u’bakar – cattle (see Devarim 16:2). We know, however, that only certain types of cattle can be used for the korban Pesach – specifically a lamb or a goat (see Shemot 12:5). The Mishnah concludes that the purpose of using a broader term – “cattle” – is to connect other sacrifices to the korban Pesachso that we can conclude that just as the korban Pesach is brought from personal funds and not sanctified money (since at the time when the first koban Pesach was brought the laws of sanctified money did not yet exist), similarly, all other obligatory sacrifices must come from personal funds and not from sanctified money.
The aharonim ask why we need to find a source in the Torah to teach that obligatory sacrifices cannot be brought fromma’aser sheni money. While it is reasonable to demand a biblical source for cases where the obligation to bring a sacrifice was created by the person himself – e.g. if he said “I accept upon myself a korban todah” – in cases where the person is truly obligated to bring a sacrifice – e.g. someone who must bring a sin offering or a guilt offering – it would appear obvious that he cannot fulfill his obligation with sanctified money.
In his Olat Shlomo, Rav Shlomo Zalman Lifshitz suggests that we can understand this according to the approach suggested by the Rambam (whose source is in the Talmud Yerushalmi). The Rambam believes that once an animal is purchased for sacrifice using ma’aser sheni money, the sanctity of the ma’aser sheni is removed and replaced with the new sanctity of the sacrifice. Based on this perspective, one may have thought that other sacrifices could remove thema’aser sheni sanctity, as well; we need the parallel to korban Pesach to teach that this is not the case.