Pesachim 108a: Do the Four Cups Require Heseba?

Full Summary

This shiur examines Pesachim 108a's discussion of whether the four cups at the Seder require heseba (reclining). The Gemara (גמרא) presents a dispute between those who say the first two cups need heseba versus those who say the last two, leading to the question of whether safek d'rabbanan l'kula should apply, allowing us to choose just two cups rather than requiring all four. The Ran initially suggests that since we don't know which two cups require heseba, we must do all four to avoid completely nullifying the rabbinic decree (mevatel takanas chachamim). The Mishna Melech develops this approach, distinguishing between cases where the uncertainty affects the individual's fulfillment of a mitzvah (מצוה) versus cases where it would undermine the entire rabbinic institution. He contrasts this with megillah reading, where doing one day is sufficient because it doesn't nullify the takanas chachamim - the decree for both types of cities remains intact. However, Rabbi Zweig challenges this interpretation by examining the practical halacha (הלכה). The Shulchan Aruch and Rama rule that if someone forgot to recline while drinking the cups, they must repeat all four cups with reclining. If the Mishna Melech's interpretation were correct, once the takanas chachamim is established (everyone else does four cups), an individual's mistake should only require two cups according to safek d'rabbanan l'kula. The fact that halacha requires repeating all four suggests a different understanding. Rabbi Zweig proposes that the Ran's actual position is that when someone is definitively obligated in a mitzvah (vadai mechuyav), they must ensure they fulfill it completely. The four cups with heseba constitute one unified mitzvah, not separate obligations. If someone is vadai mechuyav in heseba but uncertain whether they fulfilled it, they cannot rely on safek d'rabbanan l'kula because they are definitely obligated in the mitzvah. This differs from megillah, which involves two separate obligations (city dwellers versus walled city dwellers), where uncertainty about which category applies allows for safek d'rabbanan l'kula. The Ran's distinction is not about nullifying takanas chachamim but about the fundamental principle that when one is vadai mechuyav in a mitzvah, they must vadai fulfill it.