Preparations for the Seder
11. A son attending a Seder in his father's presence is obligated to
recline (1). In contrast, a student attending a Seder in his Rebbe's
(teacher) presence need not recline (2).
(1) It is a mitzvah on the night of Pesach to act and feel as if you,
yourself, were just freed from slavery in Egypt; this is derived from the
verse "and you shall remember that YOU were a slave..." (Deut 5:15), and
the verse which tells us to tell our children that "He took US out of
there" (Deut 6:23). The Sages established the mitzvah of reclining to the
left during the seder, as an outward expression of this newfound freedom,
because royality and nobility in those days reclined while eating (Rambam,
'Yad', Chometz U'Matzah 7:7).
There is one authority who rules that since nowadays it is not the custom
of nobility to recline, we are not obligated to recline during the seder.
However most authorities disagree and rule that if one did not recline
while performing the mitzvah of eating matzah (including "Korech" and
"Afikoman"), and drinking the four cups of wine, then one has not fulfilled
his obligation and must eat or drink again. It is preferable (but not
obligatory) to recline while eating and drinking the entire seder meal.
Although it would be generally considered disrespectful for a son to
recline in his father's presence, we assume that the father forgoes this
outward sign of respect on the Seder night, so that his son can perform the
mitzvah (this is true even if the father is also his son's teacher) (Mishna
(2) According to the Talmud, the reverence a student must have for his
Rebbe is comparable to the reverence he must have for G-d. Therefore, if
the student has not received permission from his Rebbe to recline, it would
be prohibited for him to recline. Some authorities rule that if the Rebbe
gives permission for the student to recline, then the student is obligated
to recline ( Mishna Berura 472:16).