The Yizkor Prayer

What is Yizkor. Why do some people leave the synagogue when it's recited. How old is this custom? Why is it said on the Chag?

Shalom!

Thank you for your question.

Yizkor is the special memorial prayer that is recited several times a year, according to the Ashkenazi custom, on Yom Kippur, the last day of Pesach, on Shavuot (the second day of Shavuot outside of Israel) and on Shemini Atzeret. It is a prayer that G-d elevate the souls of the deceased to even higher and greater places in Heaven. 

It is a universal practice to make a pledge to charity (Bli Neder) when reciting Yizkor as we believe that such good deeds done in memory of the deceased also serves to uplift their souls.

It seems that the origins of Yizkor derive from the Midrash (Tanchuma, Ha’azinu 1), where it cites the verse (Deut 21:8) “Atone for Your people, Israel, whom You have redeemed” and explains that “...your people whom You have redeemed” refers to the deceased who also require atonement. The Midrash says that for this reason that Yizkor is recited on Yom Kippur which is the Day of Atonement for both the living and the dead. It later became customary to recite it on the other holidays, as well.

There are different customs as to whether Yizkor should be recited in the first year after the passing of a loved one. Some do not do so as the loss is still fresh. Others make no distinction and encourage the recitation of Yizkor no matter how soon it is after the death. Le'halocho during the first year one should stay in the synagogue during the recitation of Yizkor, but should not recite Yizkor prayer.

As you correctly note, those who have no need to recite Yizkor leave the synagogue when it is recited. One of the reasons for this is that it is said to be bad luck to remain in the synagogue for Yizkor if one has np need to do so. Others explain that it is a sign of respect to leave when one’s parents alive. Others explain the custom to leave the synagogue so that younger members do not have to witnesses the crying that is often common during Yizkor.

Sources: OC 284 and 621 and commentaries, Gesher Hachaim 1:31, Maharil, Hilchot Sukkah, Kav Hayashar 86, Yalkut Hagershoni 621:2; Shaarei Ephraim 10:31, Kitzur Shulchan Aruch 133:17