We have learned that it is reasonable to assume that an animal that is seen nursing must have given birth to the animal that is suckling from it, and we can conclude that any subsequent offspring do not have the sanctity of a firstborn. What if circumstances seem to indicate that the nursing animal cannot be the mother’s offspring?
On today’s daf (=page) we learn that Rabbah bar bar Hanah quotes Rabbi Yohanan as teaching that if an animal that has the appearance of a pig is following a sheep and nursing from her, we can nevertheless assume that it was born of the sheep and that the laws of bekhor will not apply to the next animal that she gives birth to. At the same time, it would be forbidden to slaughter and eat the animal that looks like a pig – even though we would do so if we were certain that it was born from a kosher animal – “until he comes and teaches righteousness to you.”
This expression “until he comes and teaches righteousness to you” is taken from a passage in Hoshea (10:12), and, as presented by Rabbi Yohanan, appears to refer to God. That is to say, we must wait until there is a Heavenly decree telling us how to rule in this case. Rashi explains that this is based on a well-established concept in Rabbinic literature, that certain questions are left unanswered until the arrival of Elijah who will serve as God’s representative to clarify areas of law that could not be determined.
Some aharonim ask how Rashi could suggest that Rabbi Yohanan rules that waiting for Elijah will solve this conundrum, since according to Rashi in Masechet Shabbat (daf 118b) we cannot accept Elijah’s rulings based on prophecy, since we believe that “Torah is not in heaven.” The generally accepted response to this question is one offered by the Hatam Sofer– that although Elijah cannot offer rulings on matters of Jewish law based on prophecy, nevertheless he can do so based on his insight and intellect.