I said Ya'aleh Veyavo in Shacharit. Why does Musaf skip it?
In Shacharit, Rosh Chodesh gets its own paragraph inside Retzeh. Here the same blessing is plain. Machzor Vitry (an early prayer book from France, around 1100) says it in one line: in Musaf, one does not say Ya'aleh Veyavo. It adds that this is the custom "in the two academies," which seems to mean the two great Torah schools of Babylonia.
Start with where the Gemara puts the paragraph. Rabbi Oshaya (a sage of the Gemara) teaches that on days with a Musaf offering, such as Rosh Chodesh, the evening, morning and afternoon prayers add a passage fitting the day to the service blessing. Musaf is not on that list.
Musaf has something those prayers lack: a blessing of its own for the day. The Rambam (Maimonides, Egypt, died 1204) describes the Rosh Chodesh Musaf as seven blessings, with a middle one that fits the Rosh Chodesh offering. In the other prayers the day is added to a blessing about something else, the service. In Musaf it gets a whole blessing.
The rulings treat Musaf as mentioning the day. The Tur (a law code, Spain, 1300s) quotes a teaching that a prayer leader who forgot Rosh Chodesh in Shacharit is not sent back, "because the Musaf prayer is before him." The Mishnah Berurah (a central commentary on daily Jewish law, written around 1900) reports that the Kenesset HaGedolah, a commentary on the Shulchan Aruch (the main code of Jewish law), says a person who forgot it in Shacharit and only realized after Musaf is covered after the fact, since he mentioned the holiness of the day in Musaf. Others say an individual always goes back.
None of these sources says in one sentence, "Musaf skips it because it has its own blessing." Machzor Vitry comes closest. In the same passage it asks why Shabbat, which has a blessing of its own, would also be mentioned in the service blessing. That logic fits Musaf: the Gemara's list leaves Musaf out, the Rambam gives Musaf its own blessing, and the rulings count Musaf as mentioning the day.
Machzor Vitry, Laws of Shabbat 131:2,Shabbat 24a,Rambam, Laws of Prayer 2:10,Tur, Orach Chaim 422,Mishnah Berurah 422:4I can make up a missed Shacharit at Mincha. Why not a missed Musaf?
It is true. The Shulchan Aruch (the main code of Jewish law) says that someone who missed Shacharit by mistake or by force prays Mincha twice, the second for makeup. For Musaf it says the opposite: if the whole day passes, there is no makeup.
The reason starts in Berakhot 26a. The Gemara asks whether prayer is like an offering, which belongs to its day, so that once the day passes the offering is canceled. Or is it a plea for mercy, which a person can make whenever he wants? For ordinary prayers the Gemara answers with a teaching of Rabbi Yochanan: someone who forgot Mincha prays Maariv twice, and the worry that "its day has passed, its offering is canceled" does not apply.
Musaf is where the offering side wins. The Beit Yosef (Rabbi Yosef Karo's commentary on the Tur) quotes the early authorities. The seven blessings of Musaf were set up only because of the verse "we will pay with bulls our lips" (Hoshea 14:3). For this prayer, once its time has passed, its offering is canceled. The other prayers are requests for mercy. The Rashba (a medieval Spanish rabbi) adds two reasons: the Musaf offering cannot be mentioned once its day has passed, and there is no offering at night.
The Mishnah Berurah puts it simply. Musaf mentions the Musaf offering, and the Musaf offering has no makeup. The other prayers do not mention an offering at all.
Now read Rashi's line from the first card again.
Shulchan Aruch, Orach Chaim 108:1 and 108:6,Berakhot 26a,Beit Yosef, Orach Chaim 108:6,Mishnah Berurah 286:3The innermost room was almost never entered. Why ask for the service there?
Retzeh asks God to bring the service back "to the dvir of Your house." The weekday Retzeh page explains the word: it is the Holy of Holies, the innermost room, which Melachim I 8:6 calls "the dvir of the house, the Holy of Holies." Here is the puzzle.
The Torah says the high priest may not come into that room "at all times" (Vayikra 16:2). He went in for the Yom Kippur service, which the Torah describes as atonement "once a year" (Vayikra 16:34). So the everyday service was not held there. Why ask for it to come back to a room almost nobody entered?
The commentaries we checked on this line (the Tur, the Beit Yosef, Abudarham) explain its sources and its wording, but do not raise the question. Rabbi Shlomo Kluger (a rabbi in Galicia in the 1800s), in his Chokhmat Shlomo on the Shulchan Aruch, offers a reading that speaks to it. He gives it as his own view, "in my opinion."
He starts from a teaching about which way to face. The Gemara says a person standing outside the Land of Israel aims his heart toward the Land, in the Land toward Jerusalem, in Jerusalem toward the Temple, and in the Temple toward the Holy of Holies. So all of Israel aims its hearts at one place (Berakhot 30a). The Mishnah (the earliest book of the Oral Torah) goes further: if you cannot even turn your face, aim your heart toward the Holy of Holies.
From there he reads the line as being about prayer. The Gemara calls prayer "service of the heart" (Taanit 2a). So "bring the service back to the dvir" asks that our prayer be brought from wherever we pray into that innermost room, and accepted there. On this reading, every prayer already travels toward the room almost nobody entered.
This is one reader's explanation, given in the first person. The facts under it, that prayer is aimed at the Holy of Holies, come straight from the Gemara and the Mishnah.
Vayikra 16:2 and 16:34,Chokhmat Shlomo on Shulchan Aruch, Orach Chaim 120:1,Berakhot 30a,Mishnah Berakhot 4:5,Taanit 2a