Jews commemorate the anniversary of the death of loved ones by lighting a small candles, called a yahrzeit candle, which burns throughout the 24-hour day of the anniversary of death. The flame of the candle is a potent symbol of the flame of life that once burned brightly and illumined the lives of loved ones who mourn the loss. The date of the anniversary of the death of a loved one is determined by the Hebrew calendar.
I am frequently asked: On what other occasions during the year do we light yahrzeit candles? Is there something we say to accompany the lighting of yahrzeit candles? For whom precisely does one light a yahrzeit candle? Is lighting a candle halakhah (law) or minhag (custom)? On Yizkor, do we light one candle for all our loved ones who have died, or one candle for each relative?
First, lighting a yahrzeit candle in memory of a loved one is a lovely minhag (custom). While it is not required by halakhah (Jewish law), it is so deeply ingrained in Jewish life, it is difficult to imagine not doing so, and doing so honors the memory of those no longer with us in life. Traditionally, the relationships for whom we light a candle are the same as those for whom we say Kaddish: parents, spouse, siblings, and children. Some authorities say one should only light a candle on yahrzeit -- the anniversary of the death -- but most agree that we light yahrzeit candles for Yizkor (the memorial service), as well. Virtually all agree that lighting one candle for all relatives is sufficient. Hence, there are four times a year one lights a yahrzeit candle, in addition to the yahrzeit date itself: Yom Kippur and the three pilgrimage festivals (Pesach, Shavuot, and Sukkot). In the case of the festivals, Yizkor is recited on the last day of the festival, which means the eighth day of Pesach, the second day of Shavuot, and Shemini Atzeret.
Since it is forbidden kindle a flame on a chag (holy festival day) as on Shabbat, the Yizkor candle should be lit from an existing flame, such as the pilot light of a gas stove, or an already lit candle (many people light another yahrzeit candle prior to sundown on chag to use for this purpose). When the yahrzeit falls on Shabbat, the yahrzeit candle should be lit prior to lighting Shabbat candles, since the lighting of Shabbat candles initiates Shabbat and no flame may be lit after that until Shabbat ends. If the yahrzeit falls on Sunday, the candle should be lit Saturday night after Havdalah. (We follow the same procedure for lighting Chanukah candles as well: On Friday evening, we light the Chanukah candles before the Shabbat candles, and on Saturday evening we make Havdalah first and light the Chanukah candles afterward.)
There are no prescribed prayers to recite when one lights a yahrzeit candle. However, I have prepared some prayers which you might wish to use that are mailed to members prior to yahrzeit (if the synagogue has a record of the date of death of your loved one). In addition, I encourage you to recite whatever prayer is in your heart; the prayers of the heart are especially precious to God.
Yahrzeit candles, which can be purchased in most supermarkets, are designed to burn more than 24 hours so they will remain burning throughout the yahrzeit. The flame of the candle symbolizes the flame of the human soul which is never extinguished and which continues to burn brightly in our lives, especially when we honor the memory of our loved ones.
In recent years, I have seen electric yahrzeit candles, which are small lamps which plug into the wall. I imagine that these satisfy the needs of those who fear having an open flame burning in the house for 24 hours. Since lighting a yahrzeit candle is a minhag (custom) and not a matter of halakhah (law) there is no reason to object to these, though I have a sense that something is loss in substituting an electric bulb for a genuine flame.