MUSAF (Heb. מוּסָף), the additional sacrifice or prayer instituted on the Sabbath and the festivals. In addition to the daily morning and afternoon sacrifices offered in the Temple, the Bible prescribed additional offerings to be brought on Sabbaths, the three *Pilgrim festivals, Rosh Ha-Shanah, the Day of Atonement, and the New Moon (Num. 28–29; see *Sacrifice). These were offered after the regular morning sacrifices (Yoma 33a). An additional prayer was already recited on these days by some worshipers even when the sacrificial cult still existed (Tosef., Ber. 3:3; Suk. 53a). After the abolition of sacrifice with the destruction of the Temple, the additional prayer was formalized and took the place of these sacrifices (Ber. 26b; see *Prayer, *Liturgy). There were some tannaim who regarded the Musaf prayer service as exclusively communal, and they held that it could only be recited when one worshiped with a quorum (*minyan; Ber. 4:7 and Ber. 30a–b). The rabbis, however, made the additional service obligatory upon every individual, both when praying alone or with a quorum, and they endowed it with the same importance as the regular morning service (Ber. 30b; Sh. Ar., OḤ 286:2).
It is customary to recite the Musaf service immediately after the reading of the weekly Torah and haftarah portions which follow the morning prayers on Sabbaths and festivals. It is, however, permissible to recite it at any time during the day. Nevertheless, one who negligently postpones its recitation until after the seventh hour of the day is considered a "transgressor" (Ber. 4:1 and Ber. 26b, 28a).
The Musaf is introduced by the reader's recitation of the Half *Kaddish. This is followed by the Musaf *Amidah which, except on Rosh Ha-Shanah, consists of seven benedictions. The first three benedictions of praise and the last three benedictions of thanks are identical with those of the daily Amidah. The benediction Kedushat ha-Yom ("Sanctity of the Day") is inserted between these blessings. It consists of an introductory paragraph, followed by a prayer for the restoration of the Temple service, and concludes with the appropriate selection from the Torah detailing the additional sacrifice for the day. In the Musaf for Rosh Ha-Shanah three blessings are added in the middle: the *malkhuyyot (malkhiyyot), *zikhronot, and *shofarot. In communal prayer, the Musaf Amidah is generally repeated in full by the ḥazzan (Rema to Sh. Ar., OḤ 286:2). In some congregations, however, particularly among the Sephardi Jews, the ḥazzan chants the first three blessings aloud with the congregation. This, however, is not done on the High Holy Days, when the entire Amidah is always repeated by the ḥazzan.
The Sabbath Musaf Amidah, after the initial three regular blessings, consists of a composition in which the initial letters of the first 22 words follow the inverted order of the Hebrew alphabet. This prayer concludes with the description of the Sabbath Musaf offering from Numbers 28:9–10. A short prayer for those who observe the Sabbath follows, and the "Sanctity of the Day" concludes with the prayer beginning with the invocation "Our God and God of our fathers," common to all the Amidot of the Sabbath (Hertz, Prayer, 530–4).
On New Moons, the Musaf consists of a prayer expressing sorrow over the abolition of the sacrificial ritual and hope for its restoration. Numbers 28:11, describing the New Moon sacrifice, is quoted, and it concludes with a prayer for a blessed and happy month (ibid., 778–82). When the New Moon falls on a Sabbath, the first prayer is greatly altered and is very similar to the corresponding formula for the festivals. It concludes with the quotations from Numbers for both Sabbaths and New Moon offerings (ibid., 542–4).
The Musaf Amidah for the three festivals begins with the prayer "But on account of our sins we were exiled from our land." God is asked to gather the scattered remnant of Israel to the Holy Land and to build the Temple. The appropriate passage detailing the Musaf offering is then inserted, and the regular prayer for the blessings of the festival concludes this section (ibid., 820–8).
The Musaf service for the New Year is the longest in the liturgy. It opens with the same format as the other Amidot of that day, followed by the prayer "But on account of our sins," and concludes with the selection from Numbers 29:1–2 describing the Musaf sacrifice. After this, Aleinu is recited, followed by the above mentioned three additional benedictions.
The Musaf Amidah for the Day of Atonement begins in the same way as that of the New Year. After the biblical selection in which the additional sacrifices for the day are detailed (Num. 29:7–8), a prayer for the forgiveness of sins is recited. The *Confession (see *Al Ḥet; *Ashamnu) forms an integral portion of this Musaf service, just as it does in the other Amidot of the Day of Atonement.
It was customary to interlace the ḥazzan's repetition of the Musaf Amidah on festivals and special Sabbaths with various piyyutim. Except for Rosh Ha-Shanah and the Day of Atonement, this is hardly done nowadays. Even on those two holidays most modern congregations recite only selections from the huge volume of piyyutim composed throughout the generations.
The Musaf services of the first day of Passover and of Shemini Aẓeret are known by special names: the former as Tal ("dew"), because prayers for abundant dew are recited during the repetition of the first two blessings by the cantor; the latter as Geshem ("rain"), because prayers for rain are recited by the cantor at the same juncture. (In Israel, the custom is to recite these two prayers before Musaf.)
In Reform congregations in the 19th century the Musaf service was either entirely abolished or modified, since Reform Judaism no longer anticipated the restoration of the sacrificial cult. In the course of time, the tendency was to omit it entirely. Some Conservative congregations have rephrased references to the sacrifices so that they indicate solely past events without implying any hope for a future restoration of sacrifice.
Elbogen, Gottesdienst, 115–7 and index; Idelsohn, Liturgy, 142–4, 284; E. Levy, Yesodot ha-Tefillah (19522), 45–47; J. Heinemann, Ha-Tefillah bi-Tekufat ha-Tanna'im ve-ha-Amora'im (19662), 34, 172; J.J. Petuchowski, Prayerbook Reform in Europe (1968), 240–64, index (for Reform usage).