Pidyon Haben, Bris Milah, and Mitzvos She'Zman Geramah: When Time Creates Obligation

This shiur on Kiddushin 29a begins with a practical question: when do you make the seudah for a mitzvah (מצוה)—before or after? At a bris, the meal often comes first. At pidyon haben, the meal precedes the mitzvah. But at a siyum during the Nine Days, you do the siyum first, then eat. Rabbi Zweig uses this to introduce a fundamental principle: seudas mitzvah is not about celebrating the mitzvah itself, but about marking a life-cycle change. According to Rashi (רש"י), pidyon haben has a seudas mitzvah because it marks the child becoming a bar kayama—no longer a safek nefel. The Gemara (גמרא) in Bava Kamma 80a records a dispute whether Rav Shimon and Rav Asi were going to a "shavu'i haben" (bris) or "yeshu'i haben." Rashi says yeshu'i haben is pidyon haben. Tosfos says it refers to shalom zachor, celebrating the child's escape from danger at birth. This dispute reflects a deeper machlokes: Rashi holds pidyon haben's thirty-day waiting period is to ensure the child is not a nefel. Tosfos (in Yevamos 11a) asks that if the child has kol chodashav (full development), there's no safek nefel, so why wait thirty days? Tosfos holds thirty days is simply a gezeiras hakasuv. The shiur explores when a seudah is permitted: wherever the life-cycle change happened before the mitzvah (like thirty days passing), you can eat first, then do the mitzvah to explain the change. But where the mitzvah itself creates the change (like at a bris), the seudah follows.