Siman 283

The reason we do not take out a second sefer on Shabbat for the reading of the maftir, to read "And on the Shabbat day" as on Yom Tov, is because it contains only two verses. To begin earlier is not of the subject matter, and it is not similar to Rosh Chodesh where there are four called to the Torah. Furthermore, the primary purpose of reading the sacrifices is to atone for our sins, as it is stated in Taanit (27b), and in the Musaf of Shabbat there is no sin-offering for atonement (Tur). And even though burnt-offerings also atone for those liable for positive commandments—nevertheless, their primary purpose is as a gift, and they only atone incidentally (Zevachim 7b, and see there in Tosafot). Furthermore, on Yom Tov, since in any case they have interrupted the order of the Sabbaths—the Geonim enacted to read also from the section of the Musafim, but not on Shabbat. (Ran, chapter 4 of Megillah) Furthermore, if so, there would be one haftarah for the entire year, for the haftarah must be similar to the reading of the maftir. (And the Tur wrote that therefore we say in Musaf: "You established Shabbat, You desired its sacrifices," because it has no sin-offering, see there. That is to say, a sin-offering is not for "desire," and it is better that one should not sin. Therefore, on Rosh Chodesh we say: "And the male goats we shall perform with desire," for in the future to come there will be no sin, and then even the goats of the sin-offerings will be for desire.)

Regarding the obligations—there are no fixed laws in this matter but rather customs, and in the enactments of the Maharal of Prague it is brought that the first is a groom on his wedding day or on the Shabbat after the wedding, and after him a bar mitzvah, and after him the groomsmen, and after them the mohel, and after him the sandak, and after him the husband of a woman who has given birth, and after him the yahrtzeit (Eliyahu Zuta on the Levush).

There is one who wrote that a groom on the day of the wedding precedes all those with obligations, and the Shabbat before the wedding when he is a bachelor—he is equal to a bar mitzvah, and they shall cast lots between the two of them. After them is the husband of a woman who has given birth when she goes to the beit knesset after the birth, and after him a groom after the wedding if he was a bachelor or she was a virgin, and the wedding was from Wednesday onwards. Afterwards are the participants of a brit milah: and the sandak precedes the father of the son, and the father of the son precedes the mohel, and the husband of a woman who gave birth to a daughter precedes the father of the child before the milah, if the milah is not on Shabbat itself, and similarly a yahrtzeit precedes him. And the yahrtzeit is last among all those with obligations, except for the father of the child on the day before the milah (Magen Avraham), and according to this, they certainly precede the mohel. (Even though in the Magen Avraham it is not explicitly stated to divide between whether the milah is on Shabbat itself or whether it will be afterwards, see there, nevertheless it appears to me that this is so.) And there are other customs, and every river follows its own course (ibid.).