10. It is customary [for males] to wear a kittel (1) (white robe) at the
Seder, and it should be prepared before Yom Tov begins. A mourner, may G-d
protect us, should not wear such a garment (2). He is, however, obligated
to recline at the Seder (3). Nevertheless, if he has not observed any
aspects of mourning before the commencement of Yom Tov, for example, if he
buried his dead on Yom Tov itself, it is customary not to recline. He
must, however, recite Hallel (4), for Hallel is an obligation.
(1) The kittel is worn in honor of Yom Tov. According to the Midrash, it
resembles the "clothes" of Angels, and is therefore a symbol of joy.
Another reason for wearing it is proposed by the commentators: since it is
customary for a Jewish male to be buried in his kittel, wearing it is a
reminder of the day of death, and prevents a person from becoming too
haughty and frivolous as a result of the obligation to act and feel like
royalty during the Seder.
(2) Since the primary reason for wearing the kittel is for the joy and
honor of Yom Tov, it is not fitting for a mourner to adorn himself in such
(3) As we saw in HY 118:6, it is a mitzvah on the night of Pesach to act
and feel as if you, yourself, were just freed from slavery in Egypt. The
Sages established the mitzvah of leaning to the left during the seder, as
an outward expression of this newfound freedom; royality and nobility in
those days reclined while eating (Rambam, 'Yad', Chometz U'Matzah 7:7).
(4) "Hallel" consists of selected paragraphs from Psalms.