Q&A: Gezerah Shavah and Binyan Av in Daf Yomi
Gezerah Shavah and Binyan Av in Daf Yomi
Question
With God’s help,
Hello Rabbi,
I came across in Daf Yomi (Shabbat 131a) a gezerah shavah from preparatory acts for the commandment of the omer, which override the Sabbath, to preparatory acts for the commandment of the two loaves, which override the Sabbath.
And the Talmud says: “It is available for exposition, for if it were not available for exposition, there would be a refutation…”
I remember that a gezerah shavah is not supposed to be subject to refutations (as opposed to an a fortiori argument and a binyan av). Does the meaning of the Talmud’s statement imply that if the gezerah shavah is not available for exposition, then the derivation is בעצם a binyan av and not a gezerah shavah?
Thank you,
Answer
Apparently yes. There needs to be some indication (such as the term being available for exposition) that we should compare laws between two different passages on the basis of a gezerah shavah—that is, when the similarity does not allow for a regular analogy (a binyan av).