(Heb. Musaf) Prayer service added after the Morning Service on Sabbaths, the New Moon, Pilgrim Festivals, and the High Holidays (Rosh Ha-Shanah and the Day of Atonement). On each of these days, the Bible enjoins the bringing of an additional (musaf) sacrifice or sacrifices, to supplement the tamid morning sacrifice brought daily throughout the year. The specific Sacrifices and Offerings are detailed in Numbers 28:9-29:39. Just as the Shaḥarit (Morning) Service is recited in place of the shaḥarit sacrifice, so the Musaf ("Additional") Service is recited in place of the musaf sacrifices brought on the above-mentioned days. According to the Talmud (Suk. 53a), however, a Musaf prayer was already known in the Second Temple era.
Ideally, the service should take place with a prayer quorum (Minyan), but it is obligatory even if there is no quorum, in which case one recites it alone. The Additional Service is generally recited immediately after the Morning Service Torah reading (often after a sermon), but this is chiefly a matter of convenience. There is no halakhic reason for reciting the Additional Service at that time, and it is independent of the Morning Service. The Musaf prayers may be said any time after sunrise, and should ideally be recited no later than an hour after midday (the midway point between sunrise and sunset). If one has not said them by the latter time, they may still be recited until sunset.
Half Kaddish is recited before the Additional Service, which consists of a special Amidah prayer, with the standard three preliminary and three concluding benedictions of the Amidah. Except for the Additional Service of Rosh ha-Shanah (the New Year), all the Amidah prayers contain a single middle blessing. It reflects on the importance of the day, asks God to restore the Jews to their land and Temple, and quotes the verse or verses relating to the musaf sacrifice that was offered in the Temple on that particular day. When the New Moon falls on a Sabbath, the normal Tikkanta Shabbat section is repIaced by a special formulation, Attah Yatsarta ("You have created"), which incorporates elements of both days, including the pertinent Bible verses of both.
On Rosh ha-Shanah, the middle section of the Amidah comprises three blessings, after each of which the Shofar (ram's horn) is sounded (except on the Sabbath). These blessings are known as Malkhuyyot, in which God's kingship is proclaimed; Zikhronot, in which the merits of previous generations are recalled; and Shofarot, in which there is a reference to the blowing of the shofar on the New Year. Each of these three sections quotes a total of ten Bible verses referring to the topic of that section: three from the Pentateuch, three from the Prophets, three from the Hagiographa, and a final verse from the Pentateuch. The references to the sacrifices brought on that day are included in the Malkhuyyot section.
The Amidah of each Additional Service is first read silently by the congregation and then repeated aloud by the leader. On the New Moon and the intermediate days of the Pilgrim Festivals, the standard Kedushah is recited in the third benediction; on Sabbaths, the High Holidays and the Pilgrim Festivals (including Hoshana Rabbah), a special extended Kedushah is recited.
Outside Israel, on all holy days except the Sabbath and New Moon, the priests assemble before the Holy Ark to bless the congregation during the last benediction of the Additional Service Amidah (see Priestly Blessing). Should any of these days coincide with a Sabbath, opinions are divided as to whether the priests give their blessing or not. In Israel, priests bless the other congregants at every Additional Service .
On the first day of Passover, a special Prayer for Dew is added to the (Musaf) Amidah, a similar Prayer for Rain being chanted on Shemini Atseret. On the High Holidays, extensive piyyutim (liturgical poems)--- some of a supplicatory nature and others of praise----are added to the leader's repetition of the Amidah. An elaborate Avodah mini-service is read here on the Day of Atonement. The service is usually concluded with én K(E)-Elohénu, Alénu, and Adon Olam, Kaddish being recited at least twice before the end.
