“May the service of Your people Israel always be favorable to you. May our eyes merit to see the return to Tzion in Your compassion. Blessed are You, Hashem, Who returns His Presence to Tzion.”
On chol hamo’ed and Rosh Chodesh festive sacrifices were brought in the Temple. We commemorate these offerings with the extra Mussaf prayer, as well as the special addition of the yaleh v’yavo passage to the seventeenth blessing of Shemoneh Esrei.
The general theme of this blessing is the Temple service. Since yaleh v’yavo replaces the additional sacrifices, our Sages felt it proper to insert it in this point of Shemoneh Esrei. It is said right before concluding the blessing.
At times, out of habit, a person might finish this blessing, having forgotten to insert yaleh v’yavo. As long as he has not started the next blessing, he can still recite yaleh v’yavo and then continue as usual.
If he realized the omission after starting the next blessing, he cannot just insert yaleh v’yavo at the point where he remembers. He must return to the start of the seventeenth blessing and say yaleh v’yavo in its proper place. If one already finished reciting Shemoneh Esrei by the time he notices, he must repeat the entire Shemoneh Esrei.
There is one exception to the above rule. If a person forgot to say yaleh v’yavo on the night of Rosh Chodesh, he does not go back and correct his error. Since in the times of the Temple the new month could not be proclaimed at night, if one accidentally leaves out yaleh v’yavo it does not disqualify his nighttime Shemoneh Esrei (Shulchan Aruch 222,1).
Text Copyright © 2010 by Rabbi Daniel Travis and Torah.org