It is customary on Passover, as well as on the other Shalosh Rigalim (Sukkot and Shavuot) and Yom Kippur when Yizkor (the memorial service) is recited, to light a candle in memory of loved ones who have passed away. This practice was referenced as far back as the Talmudic times when it was recorded in Tractate Ketubot 103A that before Reb Yehuda Hanassi passed away he left instructions to light a candle when he is gone. The commentaries deduce from this that it is customary to light candles for the benefit of the deceased. The Darchei Moshe, a commentary on the Tur, quotes a Kol-Bo (O.C. Siman 610) that notes the custom of lighting a candle before Yom Kippur as atonement for a parent’s neshama (soul). Additionally, the Tractate Brachos 53A instructs us that it is forbidden to derive pleasure from candles lit in honor of the deceased. Rabbeinu Bachya, one of the early commentators on the bible, on the topic of the Menorah in the Tabernacle (Exodus 25:3), writes tangentially that it is known that the neshama (soul) derives a spiritual benefit from the lit candles.
The Sefer Gesher Hachaim (one of the premier authorities on the Laws of Mourning) tells us that the Zohar alludes to the preferred type of memorial candle which is one of olive oil [Vol 1:Chapter 20]). The Gesher Hachaim continues (in Chapter 31) that initially Yizkor was instituted on Yom Kippur only. This is alluded to by the Midrash as commentary on the plural language of the words Yom Hakippurim – that it is a day of atonement for both the living and the deceased. Over time the service was included in the prayers of the Shalosh Rigalim. He concludes with a note that the most important part of the service is the charitable pledge, for the reward of this tzedakah (charity) is given to the neshama of the deceased.
With regard to the practical application of lighting a memorial candle the time for lighting is at sundown on the eve of the Yorzeit (anniversary of a loved one’s passing) or Yizkor Service before lighting Yom Tov and/or Shabbos candles. While it is permissible to light a candle on Yom Tov from a pre-existing flame it is only allowed if the lighting of the candle were to serve a necessary need for Yom Tov. The authorities debate whether the lighting of a memorial candle falls into this category (O.C. 514.5 Biur Halacha), therefore it is preferable to use the candles that burn for forty-eight hours on Passover and Shavuot so they will still be burning on the day Yizkor is said.
If the Yorzeit falls on a Shabbos and one forgot to light a memorial candle, but remembered during the twilight period called bein hashmashos , one would be permitted to ask a gentile to kindle the candle (O.C. 261:6 M.G. citing the Marshal).
The Mateh Ephraim (Shaar 3, note section) suggests that on the Yorzeit, as well as during the days on which Yizkor is recited, the neshoma has permission to travel in the world it left behind. Therefore, on these days we light a candle to give a spiritual gratification to the soul upon seeing the lit candle in their memory.
This year’s Passover Yizkor Service will be recited on April 22nd, the twenty-second day of Nissan, which is the eighth day of Passover.